What is it?
Green tea is a product made from the Camellia sinensis plant. It can be prepared as a beverage, which can have some health effects. Or an “extract” can be made from the leaves to use as medicine.
Green tea is used to improve mental alertness and thinking.
It is also used for weight loss and to treat stomach disorders, vomiting, diarrhea, headaches, bone loss (osteoporosis), and solid tumor cancers.
Some people use green tea to prevent various cancers, including breast cancer, prostate cancer, colon cancer, gastric cancer, lung cancer, solid tumor cancers and skin cancer related to exposure to sunlight. Some women use green tea to fight human papilloma virus (HPV), which can cause genital warts, the growth of abnormal cells in the cervix (cervical dysplasia), and cervical cancer.
Green tea is also used for Crohn’s disease, Parkinson’s disease, diseases of the heart and blood vessels, diabetes, low blood pressure, chronic fatigue syndrome (CFS), dental cavities (caries), kidney stones, and skin damage.
Instead of drinking green tea, some people apply green tea bags to their skin to soothe sunburn and prevent skin cancer due to sun exposure. Green tea bags are also used to decrease puffiness under the eyes, as a compress for tired eyes or headache, and to stop gums from bleeding after a tooth is pulled.
Green tea in candy is used for gum disease.
Green tea is used in an ointment for genital warts. Do not confuse green tea with oolong tea or black tea. Oolong tea and black tea are made from the same plant leaves used to make green tea, but they are prepared differently and have different medicinal effects. Green tea is not fermented at all. Oolong tea is partially fermented, and black tea is fully fermented.
How effective is it?
Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
The effectiveness ratings for GREEN TEA are as follows:
Likely effective for...
- Genital warts. A specific green tea extract ointment (Veregen, Bradley Pharmaceuticals) is FDA-approved for treating genital warts.
- High cholesterol. Taking green tea by mouth seems to lower cholesterol levels. Research suggests that consuming 145-3000 mg of green tea catechins, an antioxidants found in green tea, daily for up to 24 weeks reduces total cholesterol and low-density lipoprotein (LDL or “bad”) cholesterol.
- Mental alertness. Drinking green tea and other caffeinated beverages seems to help people maintain mental alertness throughout the day. Combining caffeine with sugar as an “energy drink” seems to improve mental performance more than caffeine or sugar alone. Also, taking a combination of green tea extract and L-theanine for seems to improve memory and attention in people with mild mental problems.
Possibly effective for...
- Abnormal development of cells of the cervix (cervical dysplasia). Taking green tea by mouth or applying it to the skin seems to reduce cervical dysplasia caused by human papilloma virus (HPV) infection.
- Clogged arteries (coronary artery disease). Population studies suggest that drinking green tea is linked to a reduced risk of clogged arteries. The link seems to be stronger in men than women.
- Endometrial cancer. Population studies suggest that drinking green tea is linked to a reduced risk of developing endometrial cancer.
- Low blood pressure. Drinking green tea might help increase blood pressure in elderly people who have low blood pressure after eating.
- Thick, white patches on the gums (oral leukoplakia). Drinking green tea seems to decrease the size of white patches in people with oral leukoplakia.
- Osteoporosis. Research suggests that drinking green tea for 10 years is linked to increased bone mineral density. Also, early research suggests that taking a green tea compound containing 500 mg of catechins, an antioxidant in green tea, daily for 24 weeks improves bone strength in post-menopausal women with low bone density.
- Ovarian cancer. Women who regularly drink tea, including green or black tea, appear to have a lower risk of developing ovarian cancer.
- Parkinson’s disease. Drinking one to four cups of green tea daily seems to provide the most protection against developing Parkinson’s disease.
Insufficient evidence to rate effectiveness for...
- Acne. Early research suggests that applying a solution containing a certain chemical found in green tea to the skin for 8 weeks reduces acne.
- Abnormal protein buildup in the organs (Amyloidosis). Early research suggests that drinking green tea or taking green tea extracts for 12 months protects against an increase in heart mass in people with amyloidosis affecting the heart.
- Athletic performance. There is inconsistent evidence about the effects of green tea on athletic performance. Some early research suggests that taking green tea extract as a beverage does not improve breathing or performance in people undergoing endurance training. However, other early research suggests that taking seven doses of a certain green tea chemical over three days improves some breathing tests in healthy adults.
- Bladder cancer, esophadeal cancer, and pancreatic cancer. Most evidence suggests that drinking green tea is linked to a lower risk of bladder, esophageal, and pancreatic cancer. However, there is also some inconsistent evidence that suggests it might not reduce the risk of developing these cancers.
- Breast cancer. Research suggests that green tea does not seem to reduce the risk of breast cancer in Asian people. However, there is some evidence that it might reduce the risk in Asian-Americans.
- Heart disease. Population studies suggest that drinking three or more cups of green tea daily is linked to a decreased risk of death from heart disease or any cause.
- Colds and flu. Early research suggests that taking a specific formulation of green tea and theanine (Thea-flan and Suntheanine) daily for 5 months lowers the risk of developing the flu. Other early research suggests that taking a specific green tea product (ImmuneGuard) reduces cold and flu symptoms and the duration of illness.
- Colon cancer. Most evidence suggests that drinking green tea does not have any effect on colon cancer risk. However, some research suggests that consuming a high amount is linked to a reduce risk, particularly in women.
- Diabetes. Research suggests that Japanese adults, particularly women, who drink 6 or more cups of green tea daily, have a lower risk of developing diabetes. However, green tea extract does not seem to help control sugar or insulin levels in people who already have diabetes.
- Fertility. Early research suggests that taking a specific product containing chasteberry, green tea, L-arginine, vitamins and minerals (FertilityBlend) increases pregnancy rates in women who have trouble conceiving.
- Stomach cancer. There is inconsistent evidence about the effects of green tea on stomach cancer risk. One study suggests that drinking at least 5 cups of green tea daily does not reduce the risk of stomach cancer. Other research suggests that drinking at least 10 cups of green tea daily reduces the risk of stomach cancer.
- High blood pressure. There is inconsistent evidence about the effects of green tea on blood pressure. Some research shows that drinking green tea regularly can lower the risk of developing high blood pressure. However, other research shows that it has no effect on blood pressure in people with or without high blood pressure.
- Allergy to Japanese cedar (pollinosis). Early research suggests that drinking a green tea drink daily for 6 weeks before being exposed to Japanese cedar pollen can reduce allergy symptoms, including throat pain, nose blowing and tears.
- Leukemia. Population research suggests that Taiwanese people who drink higher amounts of green tea have a lower risk of developing leukemia.
- Lung cancer. There is inconsistent evidence about the effects of green tea on lung cancer risk. One study suggests that drinking at least 5 cups of green tea daily does not reduce the risk of death related to lung cancer. However, men who consume high amounts of phytoestrogens, chemicals found in green tea, have a lower risk of developing lung cancer.
- Metabolic syndrome. Early research suggests that taking 1000 mg of green tea extract daily or drinking four cups of green tea daily for 8 weeks does not improve blood pressure, cholesterol levels, or blood sugar in obese people with metabolic syndrome.
- Obesity. There is inconsistent evidence on the effects of green tea in obese people. Some early research shows that some specific green tea extracts (AR25, Exolise; Sunphenon) reduce weight in people with obesity. Other research suggests that drinking green tea can reduce body weight and body mass index (BMI) in overweight people. However some research suggests that taking green tea extracts or drinking green tea does not reduce body weight or BMI.
- Mouth cancer. Early research suggests that taking green tea extract three times daily after meals for 12 weeks increases healing responses in people with oral cancer.
- Gum disease (periodontal disease). Chewing candy that contains green tea extract seems to control plaque build-up on the teeth and reduce gum swelling. Also population research suggests that drinking green tea is linked with a reduced risk of gum disease.
- Pneumonia. Research suggests that Japanese women who drink green tea have a lower risk of death from pneumonia compared to those who don’t drink green tea.
- Prostate cancer. Men who drink more green tea or who take products containing green tea antioxidants seem to have a lower risk of developing prostate cancer. However, green tea or green tea extracts do not seem to slow the progression of prostate cancer that has already been diagnosed.
- Stress. Early research suggests that taking a specific brand of green tea extract (Teavigo) by mouth for 7 days reduces stress and increases calmness.
- Stroke. According to one study in Japan, drinking 3 cups of green tea daily seems to lower the risk of having a stroke compared to drinking one cup or no tea.
- Upper respiratory tract infection. Early research suggests that gargling and swallowing green tea (Morgentau) over 4 days is less effective than citrus lozenges (Cystus052) for reducing symptoms of upper respiratory tract infections.
- Wrinkled skin. Some early research suggests that taking green tea antioxidants twice daily for 2 years does not reduce the signs of sun damage to the face in women. However, applying a green tea cream and taking green tea by mouth daily seems to improve some aspects of skin aging in women.
- Other conditions.
More evidence is needed to rate green tea for these uses.
The useful parts of green tea are the leaf bud, leaf, and stem. Green tea is not fermented and is produced by steaming fresh leaves at high temperatures. During this process, it is able to maintain important molecules called polyphenols, which seem to be responsible for many of the benefits of green tea.
Polyphenols might be able to prevent inflammation and swelling, protect cartilage between the bones, and lessen joint degeneration. They also seem to be able to fight human papilloma virus (HPV) infections and reduce the growth of abnormal cells in the cervix (cervical dysplasia). Research cannot yet explain how this works.
Green tea contains 2% to 4% caffeine, which affects thinking and alertness, increases urine output, and may improve the function of brain messengers important in Parkinson’s disease. Caffeine is thought to stimulate the nervous system, heart, and muscles by increasing the release of certain chemicals in the brain called “neurotransmitters.”
Antioxidants and other substances in green tea might help protect the heart and blood vessels.
Green tea is LIKELY SAFE for most adults when consumed in moderate amounts. Green tea extract is POSSIBLY SAFE for most people when taken by mouth or applied to the skin for a short time. In some people, green tea can cause stomach upset and constipation. Green tea extracts have been reported to cause liver problems in rare cases.
Drinking too much green tea — more than five cups per day, for example — is POSSIBLY UNSAFE. It can cause side effects because of the caffeine. These side effects can range from mild to serious and include headache, nervousness, sleep problems, vomiting, diarrhea, irritability, irregular heartbeat, tremor, heartburn, dizziness, ringing in the ears, convulsions, and confusion. Green tea seems to reduce the absorption of iron from food. Drinking very high doses of green tea is LIKELY UNSAFE and can actually be fatal. The fatal dose of caffeine in green tea is estimated to be 10-14 grams (150-200 mg per kilogram). Serious toxicity can occur at lower doses.
Caffeine is POSSIBLY SAFE in children in amounts commonly found in foods.
Green tea interacts with many medications, as explained below.
Special precautions & warnings:
Pregnancy and breast-feeding: If you are pregnant or breast-feeding, green tea in small amounts – about 2 cups per day – is POSSIBLY SAFE. This amount of green tea provides about 200 mg of caffeine. However, drinking more than 2 cups of green tea per day is POSSIBLY UNSAFE. Consuming more than 2 cups of green tea daily has been linked to an increased risk of miscarriage and other negative effects. Also, caffeine passes into breast milk and can affect a nursing infant. Don’t drink an excessive amount of green tea if you are pregnant or breast-feeding.
“Tired blood” (anemia): Drinking green tea may make anemia worse.
Anxiety disorders: The caffeine in green tea might make anxiety worse.
Bleeding disorders: Caffeine in green tea might increase the risk of bleeding. Don’t drink green tea if you have a bleeding disorder.
Heart conditions: Caffeine in green tea might cause irregular heartbeat.
Diabetes: Caffeine in green tea might affect blood sugar control. If you drink green tea and have diabetes, monitor your blood sugar carefully.
Diarrhea. Green tea contains caffeine. The caffeine in green tea, especially when taken in large amounts, can worsen diarrhea.
Irritable bowel syndrome (IBS): Green tea contains caffeine. The caffeine in green tea, especially when taken in large amounts, can worsen diarrhea and might worsen symptoms of IBS.
Glaucoma: Drinking green tea increases pressure inside the eye. The increase occurs within 30 minutes and lasts for at least 90 minutes.
High blood pressure: The caffeine in green tea might increase blood pressure in people with high blood pressure. However, this does not seem to occur in people who regularly drink green tea or other products that contain caffeine.
Liver disease: Green tea extract supplements have been linked to several cases of liver damage. Green tea extracts might make liver disease worse.
Weak bones (osteoporosis): Drinking green tea can increase the amount of calcium that is flushed out in the urine. Caffeine should be limited to less than 300 mg per day (approximately 2-3 cups of green tea). It is possible to make up for some calcium loss caused by caffeine by taking calcium supplements.
Do not take this combination.
Stimulant drugs such as amphetamines speed up the nervous system. By speeding up the nervous system, stimulant medications can make you feel jittery and increase your heart rate. The caffeine in green tea might also speed up the nervous system. Taking green tea along with stimulant drugs might cause serious problems including increased heart rate and high blood pressure. Avoid taking stimulant drugs along with caffeine.
Stimulant drugs such as cocaine speed up the nervous system. By speeding up the nervous system, stimulant medications can make you feel jittery and increase your heart rate. The caffeine in green tea might also speed up the nervous system. Taking green tea along with stimulant drugs might cause serious problems including increased heart rate and high blood pressure. Avoid taking stimulant drugs along with caffeine.
Stimulant drugs speed up the nervous system. Caffeine (contained in green tea) and ephedrine are both stimulant drugs. Taking green tea along with ephedrine might cause too much stimulation and sometimes serious side effects and heart problems. Do not take caffeine-containing products and ephedrine at the same time.
Medications moved by pumps in cells (Organic Anion-Transporting Polypeptide Substrates)
Some medications are moved by pumps in cells. Green tea might change how these pumps work and decrease how much of some medications get absorbed by the body. This could make these medications less effective.
Some of these medications that are moved by pumps in cells include bosentan (Tracleer), celiprolol (Celicard, others), etoposide (VePesid), fexofenadine (Allegra), fluoroquinolone antibiotics, glyburide (Micronase, Diabeta), irinotecan (Camptosar), methotrexate, nadolol (Corgard), paclitaxel (Taxol), saquinavir (Fortovase, Invirase), rifampin, statins, talinolol, torsemide (Demadex), troglitazone, and valsartan (Diovan).
Green tea might decrease how much nadolol (Corgard) the body absorbs. Taking green tea along with nadolol (Corgard) might decrease the effectiveness of nadolol (Corgard).
Be cautious with this combination.
Green tea contains caffeine. The caffeine in green tea might block the effects of adenosine (Adenocard). Adenosine (Adenocard) is often used by doctors to do a test on the heart, called a cardiac stress test. Stop consuming green tea or other caffeine-containing products at least 24 hours before a cardiac stress test.
Antibiotics (Quinolone antibiotics)
The body breaks down caffeine to get rid of it. Some antibiotics might decrease how quickly the body breaks down caffeine. Taking these antibiotics along with green tea can increase the risk of side effects including jitteriness, headache, increased heart rate, and other side effects.
Some antibiotics that decrease how quickly the body breaks down caffeine include ciprofloxacin (Cipro), enoxacin (Penetrex), norfloxacin (Chibroxin, Noroxin), sparfloxacin (Zagam), trovafloxacin (Trovan), and grepafloxacin (Raxar).
Birth control pills (Contraceptive drugs)
The body breaks down the caffeine in green tea to get rid of it. Birth control pills can decrease how quickly the body breaks down caffeine. Taking green tea along with birth control pills can cause jitteriness, headache, fast heartbeat, and other side effects.
Some birth control pills include ethinyl estradiol and levonorgestrel (Triphasil), ethinyl estradiol and norethindrone (Ortho-Novum 1/35, Ortho-Novum 7/7/7), and others.
Bortezomib (Velcade) is used in certain types of cancers. Green tea might interact with bortezomib (Velcade) and decrease its effectiveness for treating certain types of cancer. If you take bortezomib (Velcade) avoid taking green tea products.
Green tea contains caffeine. The body breaks down caffeine to get rid of it. Cimetidine (Tagamet) can decrease how quickly your body breaks down caffeine. Taking cimetidine (Tagamet) along with green tea might increase the chance of caffeine side effects including jitteriness, headache, fast heartbeat, and others.
The body breaks down clozapine (Clozaril) to get rid of it. The caffeine in green tea seems to decrease how quickly the body breaks down clozapine (Clozaril). Taking green tea along with clozapine (Clozaril) can increase the effects and side effects of clozapine (Clozaril).
Green tea contains caffeine. The caffeine in green tea might block the affects of dipyridamole (Persantine). Dipyridamole (Persantine) is often used by doctors to do a test on the heart called a cardiac stress test. Stop drinking green tea or other caffeine-containing products at least 24 hours before a cardiac stress test.
The body breaks down caffeine to get rid of it. Disulfiram (Antabuse) can decrease how quickly the body gets rid of caffeine. Taking green tea (which contains caffeine) along with disulfiram (Antabuse) might increase the effects and side effects of caffeine, including jitteriness, hyperactivity, irritability, and others.
The body breaks down the caffeine in green tea to get rid of it. Estrogens can decrease how quickly the body breaks down caffeine. Taking estrogen pills and drinking green tea can cause jitteriness, headache, fast heartbeat, and other side effects. If you take estrogen pills, limit your caffeine intake.
Some estrogen pills include conjugated equine estrogens (Premarin), ethinyl estradiol, estradiol, and others.
The body breaks down the caffeine in green tea to get rid of it. Fluvoxamine (Luvox) can decrease how quickly the body breaks down caffeine. Taking green tea along with fluvoxamine (Luvox) might cause too much caffeine in the body, and increase the effects and side effects of caffeine.
Your body naturally gets rid of lithium. The caffeine in green tea can increase how quickly your body gets rid of lithium. If you take products that contain caffeine and you take lithium, stop taking caffeine products slowly. Stopping caffeine too quickly can increase the side effects of lithium.
Medications for asthma (Beta-adrenergic agonists)
Green tea contains caffeine. Caffeine can stimulate the heart. Some medications for asthma can also stimulate the heart. Taking caffeine with some medications for asthma might cause too much stimulation and cause heart problems.
Some medications for asthma include albuterol (Proventil, Ventolin, Volmax), metaproterenol (Alupent), terbutaline (Bricanyl, Brethine), and isoproterenol (Isuprel).
Medications for depression (MAOIs)
Caffeine in green tea can stimulate the body. Some medications used for depression can also stimulate the body. Taking green tea that contains caffeine along with some medications for depression might cause serious side effects including fast heartbeat, high blood pressure, nervousness, and others.
Some of these medications used for depression include phenelzine (Nardil), tranylcypromine (Parnate), and others.
Medications that can harm the liver (Hepatotoxic drugs)
Green tea extracts might harm the liver. Taking green tea extracts along with medication that might also harm the liver can increase the risk of liver damage. Do not take green tea extracts if you are taking a medication that can harm the liver.
Some medications that can harm the liver include acetaminophen (Tylenol and others), amiodarone (Cordarone), carbamazepine (Tegretol), isoniazid (INH), methotrexate (Rheumatrex), methyldopa (Aldomet), fluconazole (Diflucan), itraconazole (Sporanox), erythromycin (Erythrocin, Ilosone, others), phenytoin (Dilantin) , lovastatin (Mevacor), pravastatin (Pravachol), simvastatin (Zocor), and many others.
Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)
Green tea might slow blood clotting. Taking green tea along with medications that also slow clotting might increase the chances of bruising and bleeding.
Some medications that slow blood clotting include ardeparin (Normiflo), aspirin, clopidogrel (Plavix), diclofenac (Voltaren, Cataflam, others), dipyridamole (Persantine), ibuprofen (Advil, Motrin, others), naproxen (Anaprox, Naprosyn, others), dalteparin (Fragmin), enoxaparin (Lovenox), heparin, ticlopidine (Ticlid), warfarin (Coumadin), and others.
Medications used to treat cancer (Boronic acid-based proteasome inhibitors)
Green tea might interact with some medications used to treat cancer (boronic acid-based proteasome inhibitors). This might decrease its effectiveness of these medications for treating certain types of cancer. If you take one of these medications for cancer, avoid taking green tea products. Some of these drugs include bortezomib (Velcade).
Stimulant drugs such as nicotine speed up the nervous system. By speeding up the nervous system, stimulant medications can make you feel jittery and increase your heart rate. The caffeine in green tea might also speed up the nervous system. Taking green tea along with stimulant drugs might cause serious problems, including increased heart rate and high blood pressure. Avoid taking stimulant drugs along with caffeine.
The stimulant effects of the caffeine in green tea can block the sleep-producing effects of pentobarbital (Nembutal).
Green tea contains caffeine. Caffeine can stimulate the body. Phenylpropanolamine can also stimulate the body. Taking green tea and phenylpropanolamine together might cause too much stimulation and increase heartbeat, increase blood pressure, and cause nervousness.
The body breaks down riluzole (Rilutek) to get rid of it. Drinking green tea can decrease how quickly the body breaks down riluzole (Rilutek) and increase the effects and side effects of riluzole.
Stimulant drugs speed up the nervous system and can make you feel jittery and speed up your heartbeat. Green tea contains caffeine, which can also speed up the nervous system. Taking green tea along with stimulant drugs might cause serious problems including increased heart rate and high blood pressure.
Some stimulant drugs include diethylpropion (Tenuate), epinephrine, phentermine (Ionamin), pseudoephedrine (Sudafed), and many others.
Green tea contains caffeine. Caffeine works similarly to theophylline. Caffeine can also decrease how quickly the body gets rid of theophylline. Taking green tea along with theophylline might increase the effects and side effects of theophylline.
Verapamil (Calan, Covera, Isoptin, Verelan)
The body breaks down the caffeine in green tea to get rid of it. Verapamil (Calan, Covera, Isoptin, Verelan) can decrease how quickly the body gets rid of caffeine. Drinking green tea and taking verapamil (Calan, Covera, Isoptin, Verelan) can increase the risk of side effects for caffeine including jitteriness, headache, and an increased heartbeat.
Warfarin (Coumadin) is used to slow blood clotting. Large amounts of green tea have been reported to decrease the effectiveness of warfarin (Coumadin). Decreasing the effectiveness of warfarin (Coumadin) might increase the risk of clotting. It is unclear why this interaction might occur. Be sure to have your blood checked regularly. The dose of your warfarin (Coumadin) might need to be changed.
Be watchful with this combination.
The body breaks down the caffeine in green tea to get rid of it. Alcohol can decrease how quickly the body breaks down caffeine. Taking green tea along with alcohol might cause too much caffeine in the bloodstream and caffeine side effects including jitteriness, headache, and fast heartbeat.
Green tea contains caffeine. The body breaks down caffeine to get rid of it. Fluconazole (Diflucan) might decrease how quickly the body gets rid of caffeine and cause caffeine to stay in the body too long. Taking fluconazole (Diflucan) along with green tea might increase the risk of side effects such as nervousness, anxiety, and insomnia.
Medications changed by the liver (Cytochrome P450 3A4 (CYP3A4) substrates)
Some medications are changed and broken down by the liver. Green tea might decrease how quickly the liver breaks down some medications. Taking green tea while taking some medications that are broken down by the liver can increase the effects and side effects of some medications. However, it is not known if this is a big concern. Talk to your healthcare provider if you are taking any medications that are changed by the liver.
Some medications changed by the liver include lovastatin (Mevacor), ketoconazole (Nizoral), itraconazole (Sporanox), fexofenadine (Allegra), triazolam (Halcion), and many others.
Medications for diabetes (Antidiabetes drugs)
Green tea contains caffeine. There is conflicting evidence that caffeine might either increase or decrease blood sugar. Diabetes medications are used to lower blood sugar. Taking some medications for diabetes along with caffeine might decrease the effectiveness of diabetes medications. Monitor your blood sugar closely. The dose of your diabetes medication might need to be changed.
Some medications used for diabetes include glimepiride (Amaryl), glyburide (DiaBeta, Glynase PresTab, Micronase), insulin, pioglitazone (Actos), rosiglitazone (Avandia), chlorpropamide (Diabinese), glipizide (Glucotrol), tolbutamide (Orinase), and others.
Green tea contains caffeine. The body breaks down caffeine to get rid of it. Mexiletine (Mexitil) can decrease how quickly the body breaks down caffeine. Taking Mexiletine (Mexitil) along with green tea might increase the caffeine effects and side effects of green tea.
The body breaks down midazolam (Versed) to get rid of it. Green tea might decrease how quickly the body breaks down midazolam (Versed). Taking green tea along with midazolam (Versed) might increase the effects and side effects of midazolam (Versed). However, it is not known if this is a big concern. Talk with you healthcare provider if you are taking midazolam.
The body breaks down the caffeine in green tea to get rid of it. Terbinafine (Lamisil) can decrease how fast the body gets rid of caffeine. Taking green tea along with terbinafine (Lamisil) can increase the risk of caffeine side effects including jitteriness, headache, increased heartbeat, and other effects.
Bitter orange, used along with caffeine or caffeine-containing herbs such as green tea, can increase blood pressure and heart rate in otherwise healthy people. This might damage the heart and blood vessels.
Caffeine-containing herbs and supplements
Green tea contains caffeine. Using green tea along with other herbs and supplements that contain caffeine might increase the effects of caffeine, and also its unwanted side effects. Some natural products that contain caffeine include coffee, black tea, oolong tea, guarana, mate, cola, and others.
Green tea contains caffeine. High doses of caffeine can lead to loss of too much calcium in the urine.
There is some concern that combining caffeine, ephedra, and creatine might increase the risk of serious unwanted side effects. One athlete who used this combination, as well as some other supplements to improve his performance, suffered a stroke. Researchers worry the stroke might have been caused by the supplements.
Ephedra (Ma Huang)
Don't take green tea with ephedra. The caffeine in green tea might increase the effects of ephedra. Using ephedra with caffeine might increase the risk of serious life-threatening or disabling conditions such as hypertension, heart attack, stroke, seizures, and death.
There is some concern that green tea might decrease the activity of folic acid, leaving the body with less than the amount of folic acid it needs.
Herbs and supplements that may slow blood clotting (Anticoagulant/Antiplatelet herbs and supplements)
Green tea contains caffeine. Caffeine may slow blood clotting. Using green tea along with other herbs and supplements that might also slow blood clotting could increase the risk of bleeding in some people. Some of these herbs include angelica, clove, danshen, garlic, ginger, ginkgo, Panax ginseng, and others.
Herbs and supplements that might harm the liver
In several cases, people who took green tea developed liver damage. Researchers worry that the damage might have been linked to the green tea. Taking green tea extracts with other herbs or supplements that might harm the liver could increase the risk of harm to the liver. Other products that might adversely affect the liver include bishop's weed, borage, chaparral, uva ursi, and others.
Green tea might reduce the absorption of iron supplements. For most people, this effect will not be enough to make a difference in their health. But people who don't have enough iron in their system would be wise to drink green tea between meals rather than with meals to lessen this interaction.
Green tea contains caffeine. Caffeine can increase how quickly the body releases magnesium in the urine.
Green tea appears to reduce absorption of iron from foods.
Adding milk to tea seems to reduce some of tea's benefits for the heart and blood vessels. Milk might bind and prevent absorption of the antioxidants in tea. But this is controversial. More research is needed to find out how important this interaction really is.
The following doses have been studied in scientific research:
AS A DRINK:
Doses of green tea vary significantly, but usually range between 1-10 cups daily. The commonly used dose of green tea is based on the amount typically consumed in Asian countries, which is about 3 cups per day, providing 240-320 mg of the active ingredients, polyphenols. To make tea, people typically use 1 teaspoon of tea leaves in 8 ounces boiling water.
APPLIED TO THE SKIN
- For headache or restoring mental alertness: tea providing is up to 250 mg of caffeine per day, or approximately 3 cups of tea per day.
- For improving thinking: tea providing 60 mg of caffeine, or approximately one cup.
- For reducing cholesterol: drinking 10 or more cups per day has been associated with decreased cholesterol levels. Theaflavin-enriched green tea extract, 375 mg daily for 12 weeks, has also been used for lowering cholesterol.
- For human papilloma virus (HPV) infections of the cervix: green tea extract, 200 mg daily alone or in combination with topical green tea ointment, for 8-12 weeks.
- For preventing Parkinson’s disease:
- Men consuming 421-2716 mg total caffeine (approximately 5-33 cups of green tea) daily have the lowest risk of developing Parkinson’s disease. However, a significantly lower risk is also associated with consumption of as little as 124-208 mg of caffeine (approximately 1-3 cups of green tea) daily.
- In women: more moderate caffeine consumption seems to be best, equivalent to approximately 1-4 cups of green tea per day.
- For human papillomavirus (HPV) infections of the cervix: green tea ointment alone or in combination with oral green tea extract, twice weekly for 8-12 weeks.
- For genital warts: a specific green tea extract ointment (Veregen, Bradley Pharmaceuticals) providing 15% kunecatechins applied three times daily to external warts for up to 16 weeks has been used.
Camellia sinensis, Camellia thea, Camellia theifera, Constituant Polyphénolique de Thé Vert, CPTV, EGCG, Epigallo Catechin Gallate, Épigallo-Catéchine Gallate, Epigallocatechin Gallate, Extrait de Camellia Sinensis, Extrait de Thé, Extrait de Thé Vert, Extrait de Thea Sinensis, Green Sencha Tea, Green Tea Extract, Green Tea Polyphenolic Fraction, GTP, GTPF, Japanese Tea, Kunecatechins, Poly E, Polyphenon E, PTV, Té Verde, Tea, Tea Extract, Tea Green, Thé, Thé de Camillia, Thé Japonais, Thé Vert, Thé Vert de Yame, Thé Vert Sensha, Thea bohea, Thea sinensis, Thea viridis, Yame Green Tea, Yame Tea.
To learn more about how this article was written, please see the Natural Medicines Comprehensive Database methodology.methodology (http://www.nlm.nih.gov/medlineplus/druginfo/natural/methodology.html).
To see all references for the Green tea page, please go to http://www.nlm.nih.gov/medlineplus/druginfo/natural/960.html.
- Nakachi, K., Suemasu, K., Suga, K., Takeo, T., Imai, K., and Higashi, Y. Influence of drinking green tea on breast cancer malignancy among Japanese patients. Jpn J Cancer Res 1998;89:254-261. View abstract.
- Ji, B. T., Chow, W. H., Hsing, A. W., McLaughlin, J. K., Dai, Q., Gao, Y. T., Blot, W. J., and Fraumeni, J. F., Jr. Green tea consumption and the risk of pancreatic and colorectal cancers. Int J Cancer 1-27-1997;70:255-258. View abstract.
- Yu, G. P., Hsieh, C. C., Wang, L. Y., Yu, S. Z., Li, X. L., and Jin, T. H. Green-tea consumption and risk of stomach cancer: a population-based case-control study in Shanghai, China. Cancer Causes Control 1995;6:532-538. View abstract.
- Sato, Y., Nakatsuka, H., Watanabe, T., Hisamichi, S., Shimizu, H., Fujisaku, S., Ichinowatari, Y., Ida, Y., Suda, S., Kato, K., and . Possible contribution of green tea drinking habits to the prevention of stroke. Tohoku J Exp Med 1989;157:337-343. View abstract.
- Wu, S., Li, F., Huang, X., Hua, Q., Huang, T., Liu, Z., Liu, Z., Zhang, Z., Liao, C., Chen, Y., Shi, Y., Zeng, R., Feng, M., Zhong, X., Long, Z., Tan, W., and Zhang, X. The association of tea consumption with bladder cancer risk: a meta-analysis. Asia Pac.J.Clin.Nutr. 2013;22:128-137. View abstract.
- Jurgens, T. M., Whelan, A. M., Killian, L., Doucette, S., Kirk, S., and Foy, E. Green tea for weight loss and weight maintenance in overweight or obese adults. Cochrane.Database.Syst.Rev. 2012;12:CD008650. View abstract.
- Yoon, J. Y., Kwon, H. H., Min, S. U., Thiboutot, D. M., and Suh, D. H. Epigallocatechin-3-gallate improves acne in humans by modulating intracellular molecular targets and inhibiting P. acnes. J.Invest Dermatol. 2013;133:429-440. View abstract.
- Bogdanski, P., Suliburska, J., Szulinska, M., Stepien, M., Pupek-Musialik, D., and Jablecka, A. Green tea extract reduces blood pressure, inflammatory biomarkers, and oxidative stress and improves parameters associated with insulin resistance in obese, hypertensive patients. Nutr.Res. 2012;32:421-427. View abstract.
- Kristen, A. V., Lehrke, S., Buss, S., Mereles, D., Steen, H., Ehlermann, P., Hardt, S., Giannitsis, E., Schreiner, R., Haberkorn, U., Schnabel, P. A., Linke, R. P., Rocken, C., Wanker, E. E., Dengler, T. J., Altland, K., and Katus, H. A. Green tea halts progression of cardiac transthyretin amyloidosis: an observational report. Clin.Res.Cardiol. 2012;101:805-813. View abstract.
- Wightman, E. L., Haskell, C. F., Forster, J. S., Veasey, R. C., and Kennedy, D. O. Epigallocatechin gallate, cerebral blood flow parameters, cognitive performance and mood in healthy humans: a double-blind, placebo-controlled, crossover investigation. Hum.Psychopharmacol. 2012;27:177-186. View abstract.
Scholey, A., Downey, L. A., Ciorciari, J., Pipingas, A., Nolidin, K., Finn, M., Wines, M., Catchlove, S., Terrens, A., Barlow, E., Gordon, L., and Stough, C. Acute neurocognitive effects of epigallocatechin gallate (EGCG). Appetite 2012;58:767-770. View abstract.
- Nguyen, M. M., Ahmann, F. R., Nagle, R. B., Hsu, C. H., Tangrea, J. A., Parnes, H. L., Sokoloff, M. H., Gretzer, M. B., and Chow, H. H. Randomized, double-blind, placebo-controlled trial of polyphenon E in prostate cancer patients before prostatectomy: evaluation of potential chemopreventive activities. Cancer Prev.Res.(Phila) 2012;5:290-298. View abstract.
- Kim, A., Chiu, A., Barone, M. K., Avino, D., Wang, F., Coleman, C. I., and Phung, O. J. Green tea catechins decrease total and low-density lipoprotein cholesterol: a systematic review and meta-analysis. J.Am.Diet.Assoc. 2011;111:1720-1729. View abstract.
- Shen, C. L., Chyu, M. C., Yeh, J. K., Zhang, Y., Pence, B. C., Felton, C. K., Brismee, J. M., Arjmandi, B. H., Doctolero, S., and Wang, J. S. Effect of green tea and Tai Chi on bone health in postmenopausal osteopenic women: a 6-month randomized placebo-controlled trial. Osteoporos.Int. 2012;23:1541-1552. View abstract.
- Brown, A. L., Lane, J., Holyoak, C., Nicol, B., Mayes, A. E., and Dadd, T. Health effects of green tea catechins in overweight and obese men: a randomised controlled cross-over trial. Br.J.Nutr. 2011;106:1880-1889. View abstract.
- Zheng, X. X., Xu, Y. L., Li, S. H., Liu, X. X., Hui, R., and Huang, X. H. Green tea intake lowers fasting serum total and LDL cholesterol in adults: a meta-analysis of 14 randomized controlled trials. Am.J.Clin.Nutr. 2011;94:601-610. View abstract.
- Zheng, J., Yang, B., Huang, T., Yu, Y., Yang, J., and Li, D. Green tea and black tea consumption and prostate cancer risk: an exploratory meta-analysis of observational studies. Nutr.Cancer 2011;63:663-672. View abstract.
- Hsu, C. H., Liao, Y. L., Lin, S. C., Tsai, T. H., Huang, C. J., and Chou, P. Does supplementation with green tea extract improve insulin resistance in obese type 2 diabetics? A randomized, double-blind, and placebo-controlled clinical trial. Altern.Med.Rev. 2011;16:157-163. View abstract.
- Heinrich, U., Moore, C. E., De, Spirt S., Tronnier, H., and Stahl, W. Green tea polyphenols provide photoprotection, increase microcirculation, and modulate skin properties of women. J.Nutr. 2011;141:1202-1208. View abstract.
- Yellapu, R. K., Mittal, V., Grewal, P., Fiel, M., and Schiano, T. Acute liver failure caused by 'fat burners' and dietary supplements: a case report and literature review. Can.J.Gastroenterol. 2011;25:157-160. View abstract.
- Matsumoto, K., Yamada, H., Takuma, N., Niino, H., and Sagesaka, Y. M. Effects of green tea catechins and theanine on preventing influenza infection among healthcare workers: a randomized controlled trial. BMC.Complement Altern.Med. 2011;11:15. View abstract.
- Park, S. K., Jung, I. C., Lee, W. K., Lee, Y. S., Park, H. K., Go, H. J., Kim, K., Lim, N. K., Hong, J. T., Ly, S. Y., and Rho, S. S. A combination of green tea extract and l-theanine improves memory and attention in subjects with mild cognitive impairment: a double-blind placebo-controlled study. J.Med.Food 2011;14:334-343. View abstract.
- Tzellos, T. G., Sardeli, C., Lallas, A., Papazisis, G., Chourdakis, M., and Kouvelas, D. Efficacy, safety and tolerability of green tea catechins in the treatment of external anogenital warts: a systematic review and meta-analysis. J.Eur.Acad.Dermatol.Venereol. 2011;25:345-353. View abstract.
- Wang, Z. M., Zhou, B., Wang, Y. S., Gong, Q. Y., Wang, Q. M., Yan, J. J., Gao, W., and Wang, L. S. Black and green tea consumption and the risk of coronary artery disease: a meta-analysis. Am.J.Clin.Nutr. 2011;93:506-515. View abstract.
- Rohde, J., Jacobsen, C., and Kromann-Andersen, H. [Toxic hepatitis triggered by green tea]. Ugeskr.Laeger 1-17-2011;173:205-206. View abstract.
- Josic, J., Olsson, A. T., Wickeberg, J., Lindstedt, S., and Hlebowicz, J. Does green tea affect postprandial glucose, insulin and satiety in healthy subjects: a randomized controlled trial. Nutr.J. 2010;9:63. View abstract.
- Hunt, K. J., Hung, S. K., and Ernst, E. Botanical extracts as anti-aging preparations for the skin: a systematic review. Drugs Aging 12-1-2010;27:973-985. View abstract.
- Stendell-Hollis, N. R., Thomson, C. A., Thompson, P. A., Bea, J. W., Cussler, E. C., and Hakim, I. A. Green tea improves metabolic biomarkers, not weight or body composition: a pilot study in overweight breast cancer survivors. J.Hum.Nutr.Diet. 2010;23:590-600. View abstract.
- Basu, A., Du, M., Sanchez, K., Leyva, M. J., Betts, N. M., Blevins, S., Wu, M., Aston, C. E., and Lyons, T. J. Green tea minimally affects biomarkers of inflammation in obese subjects with metabolic syndrome. Nutrition 2011;27:206-213. View abstract.
- Basu, A., Sanchez, K., Leyva, M. J., Wu, M., Betts, N. M., Aston, C. E., and Lyons, T. J. Green tea supplementation affects body weight, lipids, and lipid peroxidation in obese subjects with metabolic syndrome. J Am.Coll.Nutr. 2010;29:31-40. View abstract.
- Eichenberger, P., Mettler, S., Arnold, M., and Colombani, P. C. No effects of three-week consumption of a green tea extract on time trial performance in endurance-trained men. Int J Vitam.Nutr.Res. 2010;80:54-64. View abstract.
- Ichinose, T., Nomura, S., Someya, Y., Akimoto, S., Tachiyashiki, K., and Imaizumi, K. Effect of endurance training supplemented with green tea extract on substrate metabolism during exercise in humans. Scand.J Med Sci.Sports 3-10-2010; View abstract.
- Wu, Y. J., Liang, C. H., Zhou, F. J., Gao, X., Chen, L. W., and Liu, Q. [A case-control study of environmental and genetic factors and prostate cancer in Guangdong]. Zhonghua Yu Fang Yi.Xue.Za Zhi. 2009;43:581-585. View abstract.
- Richards, J. C., Lonac, M. C., Johnson, T. K., Schweder, M. M., and Bell, C. Epigallocatechin-3-gallate Increases Maximal Oxygen Uptake in Adult Humans. Med Sci.Sports Exerc. 11-27-2009; View abstract.
- Tsao, A. S., Liu, D., Martin, J., Tang, X. M., Lee, J. J., El-Naggar, A. K., Wistuba, I., Culotta, K. S., Mao, L., Gillenwater, A., Sagesaka, Y. M., Hong, W. K., and Papadimitrakopoulou, V. Phase II randomized, placebo-controlled trial of green tea extract in patients with high-risk oral premalignant lesions. Cancer Prev.Res.(Phila Pa) 2009;2:931-941. View abstract.
- Tang, N. P., Li, H., Qiu, Y. L., Zhou, G. M., and Ma, J. Tea consumption and risk of endometrial cancer: a metaanalysis. Am.J Obstet.Gynecol. 2009;201:605-608. View abstract.
- Tatti, S., Stockfleth, E., Beutner, K. R., Tawfik, H., Elsasser, U., Weyrauch, P., and Mescheder, A. Polyphenon E: a new treatment for external anogenital warts. Br.J Dermatol. 2010;162:176-184. View abstract.
- Wang, H., Wen, Y., Du, Y., Yan, X., Guo, H., Rycroft, J. A., Boon, N., Kovacs, E. M., and Mela, D. J. Effects of catechin enriched green tea on body composition. Obesity.(Silver.Spring) 2010;18:773-779. View abstract.
- Watanabe, I., Kuriyama, S., Kakizaki, M., Sone, T., Ohmori-Matsuda, K., Nakaya, N., Hozawa, A., and Tsuji, I. Green tea and death from pneumonia in Japan: the Ohsaki cohort study. Am.J Clin Nutr. 2009;90:672-679. View abstract.
- Boehm, K., Borrelli, F., Ernst, E., Habacher, G., Hung, S. K., Milazzo, S., and Horneber, M. Green tea (Camellia sinensis) for the prevention of cancer. Cochrane.Database.Syst.Rev. 2009;:CD005004. View abstract.
- Maeda-Yamamoto, M., Ema, K., Monobe, M., Shibuichi, I., Shinoda, Y., Yamamoto, T., and Fujisawa, T. The efficacy of early treatment of seasonal allergic rhinitis with benifuuki green tea containing O-methylated catechin before pollen exposure: an open randomized study. Allergol.Int 2009;58:437-444. View abstract.
- Janjua, R., Munoz, C., Gorell, E., Rehmus, W., Egbert, B., Kern, D., and Chang, A. L. A two-year, double-blind, randomized placebo-controlled trial of oral green tea polyphenols on the long-term clinical and histologic appearance of photoaging skin. Dermatol.Surg. 2009;35:1057-1065. View abstract.
- Kalus, U., Kiesewetter, H., and Radtke, H. Effect of CYSTUS052 and green tea on subjective symptoms in patients with infection of the upper respiratory tract. Phytother.Res. 2010;24:96-100. View abstract.
- Ogunleye, A. A., Xue, F., and Michels, K. B. Green tea consumption and breast cancer risk or recurrence: a meta-analysis. Breast Cancer Res.Treat. 2010;119:477-484. View abstract.
- Kushiyama, M., Shimazaki, Y., Murakami, M., and Yamashita, Y. Relationship between intake of green tea and periodontal disease. J Periodontol. 2009;80:372-377. View abstract.
- Engdal, S. and Nilsen, O. G. In vitro inhibition of CYP3A4 by herbal remedies frequently used by cancer patients. Phytother.Res. 2009;23:906-912. View abstract.
- Tang, N., Wu, Y., Zhou, B., Wang, B., and Yu, R. Green tea, black tea consumption and risk of lung cancer: a meta-analysis. Lung Cancer 2009;65:274-283. View abstract.
- Wu, M., Liu, A. M., Kampman, E., Zhang, Z. F., Van't Veer, P., Wu, D. L., Wang, P. H., Yang, J., Qin, Y., Mu, L. N., Kok, F. J., and Zhao, J. K. Green tea drinking, high tea temperature and esophageal cancer in high- and low-risk areas of Jiangsu Province, China: a population-based case-control study. Int J Cancer 4-15-2009;124:1907-1913. View abstract.
- Kakuta, Y., Nakaya, N., Nagase, S., Fujita, M., Koizumi, T., Okamura, C., Niikura, H., Ohmori, K., Kuriyama, S., Tase, T., Ito, K., Minami, Y., Yaegashi, N., and Tsuji, I. Case-control study of green tea consumption and the risk of endometrial endometrioid adenocarcinoma. Cancer Causes Control 2009;20:617-624. View abstract.
- Shimizu, M., Fukutomi, Y., Ninomiya, M., Nagura, K., Kato, T., Araki, H., Suganuma, M., Fujiki, H., and Moriwaki, H. Green tea extracts for the prevention of metachronous colorectal adenomas: a pilot study. Cancer Epidemiol.Biomarkers Prev. 2008;17:3020-3025. View abstract.
- Myung, S. K., Bae, W. K., Oh, S. M., Kim, Y., Ju, W., Sung, J., Lee, Y. J., Ko, J. A., Song, J. I., and Choi, H. J. Green tea consumption and risk of stomach cancer: a meta-analysis of epidemiologic studies. Int J Cancer 2-1-2009;124:670-677. View abstract.
- Kuo, Y. C., Yu, C. L., Liu, C. Y., Wang, S. F., Pan, P. C., Wu, M. T., Ho, C. K., Lo, Y. S., Li, Y., and Christiani, D. C. A population-based, case-control study of green tea consumption and leukemia risk in southwestern Taiwan. Cancer Causes Control 2009;20:57-65. View abstract.
- Kuriyama, S. The relation between green tea consumption and cardiovascular disease as evidenced by epidemiological studies. J Nutr. 2008;138:1548S-1553S. View abstract.
- Alemdaroglu, N. C., Dietz, U., Wolffram, S., Spahn-Langguth, H., and Langguth, P. Influence of green and black tea on folic acid pharmacokinetics in healthy volunteers: potential risk of diminished folic acid bioavailability. Biopharm.Drug Dispos. 2008;29:335-348. View abstract.
- Tatti, S., Swinehart, J. M., Thielert, C., Tawfik, H., Mescheder, A., and Beutner, K. R. Sinecatechins, a defined green tea extract, in the treatment of external anogenital warts: a randomized controlled trial. Obstet.Gynecol. 2008;111:1371-1379. View abstract.
- Sarma, D. N., Barrett, M. L., Chavez, M. L., Gardiner, P., Ko, R., Mahady, G. B., Marles, R. J., Pellicore, L. S., Giancaspro, G. I., and Low, Dog T. Safety of green tea extracts : a systematic review by the US Pharmacopeia. Drug Saf 2008;31:469-484. View abstract.
- Zhou, Y., Li, N., Zhuang, W., Liu, G., Wu, T., Yao, X., Du, L., Wei, M., and Wu, X. Green tea and gastric cancer risk: meta-analysis of epidemiologic studies. Asia Pac.J Clin Nutr. 2008;17:159-165. View abstract.
- Rowe, C. A., Nantz, M. P., Bukowski, J. F., and Percival, S. S. Specific formulation of Camellia sinensis prevents cold and flu symptoms and enhances gamma,delta T cell function: a randomized, double-blind, placebo-controlled study. J Am Coll.Nutr 2007;26:445-452. View abstract.
- Kurahashi, N., Sasazuki, S., Iwasaki, M., Inoue, M., and Tsugane, S. Green tea consumption and prostate cancer risk in Japanese men: a prospective study. Am J Epidemiol. 1-1-2008;167:71-77. View abstract.
- Federico, A., Tiso, A., and Loguercio, C. A case of hepatotoxicity caused by green tea. Free Radic.Biol Med 8-1-2007;43:474. View abstract.
- Chow, H. H., Hakim, I. A., Vining, D. R., Crowell, J. A., Cordova, C. A., Chew, W. M., Xu, M. J., Hsu, C. H., Ranger-Moore, J., and Alberts, D. S. Effects of repeated green tea catechin administration on human cytochrome P450 activity. Cancer Epidemiol.Biomarkers Prev. 2006;15:2473-2476. View abstract.
- Molinari, M., Watt, K. D., Kruszyna, T., Nelson, R., Walsh, M., Huang, W. Y., Nashan, B., and Peltekian, K. Acute liver failure induced by green tea extracts: case report and review of the literature. Liver Transpl. 2006;12:1892-1895. View abstract.
- Martinez-Sierra, C., Rendon, Unceta P., and Martin, Herrera L. [Acute hepatitis after green tea ingestion]. Med Clin (Barc.) 6-17-2006;127:119. View abstract.
- Kikuchi, N., Ohmori, K., Shimazu, T., Nakaya, N., Kuriyama, S., Nishino, Y., Tsubono, Y., and Tsuji, I. No association between green tea and prostate cancer risk in Japanese men: the Ohsaki Cohort Study. Br.J Cancer 8-7-2006;95:371-373. View abstract.
- Javaid, A. and Bonkovsky, H. L. Hepatotoxicity due to extracts of Chinese green tea (Camellia sinensis): a growing concern. J Hepatol 2006;45:334-335. View abstract.
- Chiu, A. E., Chan, J. L., Kern, D. G., Kohler, S., Rehmus, W. E., and Kimball, A. B. Double-blinded, placebo-controlled trial of green tea extracts in the clinical and histologic appearance of photoaging skin. Dermatol Surg. 2005;31(7 Pt 2):855-860. View abstract.
- Choan, E., Segal, R., Jonker, D., Malone, S., Reaume, N., Eapen, L., and Gallant, V. A prospective clinical trial of green tea for hormone refractory prostate cancer: an evaluation of the complementary/alternative therapy approach. Urol.Oncol. 2005;23:108-113. View abstract.
- Wang, L. D., Zhou, Q., Feng, C. W., Liu, B., Qi, Y. J., Zhang, Y. R., Gao, S. S., Fan, Z. M., Zhou, Y., Yang, C. S., Wei, J. P., and Zheng, S. Intervention and follow-up on human esophageal precancerous lesions in Henan, northern China, a high-incidence area for esophageal cancer. Gan To Kagaku Ryoho 2002;29 Suppl 1:159-172. View abstract.
- Sasazuki, S., Kodama, H., Yoshimasu, K., Liu, Y., Washio, M., Tanaka, K., Tokunaga, S., Kono, S., Arai, H., Doi, Y., Kawano, T., Nakagaki, O., Takada, K., Koyanagi, S., Hiyamuta, K., Nii, T., Shirai, K., Ideishi, M., Arakawa, K., Mohri, M., and Takeshita, A. Relation between green tea consumption and the severity of coronary atherosclerosis among Japanese men and women. Ann.Epidemiol. 2000;10:401-408. View abstract.
- Westphal, L. M., Polan, M. L., and Trant, A. S. Double-blind, placebo-controlled study of Fertilityblend: a nutritional supplement for improving fertility in women. Clin Exp.Obstet.Gynecol. 2006;33:205-208. View abstract.
- Nagao, T., Meguro, S., Hase, T., Otsuka, K., Komikado, M., Tokimitsu, I., Yamamoto, T., and Yamamoto, K. A catechin-rich beverage improves obesity and blood glucose control in patients with type 2 diabetes. Obesity.(Silver.Spring) 2009;17:310-317. View abstract.
- Hsu, C. H., Tsai, T. H., Kao, Y. H., Hwang, K. C., Tseng, T. Y., and Chou, P. Effect of green tea extract on obese women: a randomized, double-blind, placebo-controlled clinical trial. Clin Nutr 2008;27:363-370. View abstract.
- Matsuyama, T., Tanaka, Y., Kamimaki, I., Nagao, T., and Tokimitsu, I. Catechin safely improved higher levels of fatness, blood pressure, and cholesterol in children. Obesity.(Silver.Spring) 2008;16:1338-1348. View abstract.
- Nagao, T., Hase, T., and Tokimitsu, I. A green tea extract high in catechins reduces body fat and cardiovascular risks in humans. Obesity.(Silver.Spring) 2007;15:1473-1483. View abstract.
- Fukino, Y., Shimbo, M., Aoki, N., Okubo, T., and Iso, H. Randomized controlled trial for an effect of green tea consumption on insulin resistance and inflammation markers. J Nutr Sci Vitaminol.(Tokyo) 2005;51:335-342. View abstract.
- Van Het Hof, K. H., Kivits, G. A., Weststrate, J. A., and Tijburg, L. B. Bioavailability of catechins from tea: the effect of milk. Eur.J Clin.Nutr. 1998;52:356-359. View abstract.
- Serafini, M., Ghiselli, A., and Ferro-Luzzi, A. In vivo antioxidant effect of green and black tea in man. Eur.J Clin Nutr. 1996;50:28-32. View abstract.
- Gao, Y. T., McLaughlin, J. K., Blot, W. J., Ji, B. T., Dai, Q., and Fraumeni, J. F., Jr. Reduced risk of esophageal cancer associated with green tea consumption. J Natl.Cancer Inst. 6-1-1994;86:855-858. View abstract.
- Stockfleth, E., Beti, H., Orasan, R., Grigorian, F., Mescheder, A., Tawfik, H., and Thielert, C. Topical Polyphenon E in the treatment of external genital and perianal warts: a randomized controlled trial. Br.J Dermatol. 2008;158:1329-1338. View abstract.
- Gross, G., Meyer, K. G., Pres, H., Thielert, C., Tawfik, H., and Mescheder, A. A randomized, double-blind, four-arm parallel-group, placebo-controlled Phase II/III study to investigate the clinical efficacy of two galenic formulations of Polyphenon E in the treatment of external genital warts. J Eur.Acad.Dermatol.Venereol. 2007;21:1404-1412. View abstract.
- Sun, C. L., Yuan, J. M., Koh, W. P., and Yu, M. C. Green tea, black tea and colorectal cancer risk: a meta-analysis of epidemiologic studies. Carcinogenesis 2006;27:1301-1309. View abstract.
- Kynast-Gales SA, Massey LK. Effect of caffeine on circadian excretion of urinary calcium and magnesium. J Am Coll Nutr. 1994;13:467-72. View abstract.
- Matsuo, C., Harashima, N., Sekine, K., Kanou, M., Kanazawa, M., Ishikawa, K., Nara, Y., and Ikeda, H. [Influence of commercial soft drinks or green tea intake to occult blood and sugar tests with urinalysis reagent strips]. Rinsho Byori 2009;57:834-841. View abstract.
- Seifert, J. G., Nelson, A., Devonish, J., Burke, E. R., and Stohs, S. J. Effect of acute administration of an herbal preparation on blood pressure and heart rate in humans. Int.J.Med.Sci. 2011;8:192-197. View abstract.
- Nishikawa, M., Ariyoshi, N., Kotani, A., Ishii, I., Nakamura, H., Nakasa, H., Ida, M., Nakamura, H., Kimura, N., Kimura, M., Hasegawa, A., Kusu, F., Ohmori, S., Nakazawa, K., and Kitada, M. Effects of continuous ingestion of green tea or grape seed extracts on the pharmacokinetics of midazolam. Drug Metab Pharmacokinet. 2004;19:280-289. View abstract.
- Chan, H. T., So, L. T., Li, S. W., Siu, C. W., Lau, C. P., and Tse, H. F. Effect of herbal consumption on time in therapeutic range of warfarin therapy in patients with atrial fibrillation. J.Cardiovasc.Pharmacol. 2011;58:87-90. View abstract.
- Smits, P., Temme, L., and Thien, T. The cardiovascular interaction between caffeine and nicotine in humans. Clin.Pharmacol.Ther. 1993;54:194-204. View abstract.
- Kato Y, Miyazaki T, Kano T, et al. Involvement of influx and efflux transport systems in gastrointestinal absorption of celiprolol. J Pharm Sci 2009;98:2529-39. View abstract.
- Roth M, Timmermann BN, Hagenbuch B. Interactions of green tea catechins with organic anion-transporting polypeptides. Drug Metab Dispos 2011;39:920-6. View abstract.
- Misaka S, Yatabe J, Muller F, et al. Green Tea Ingestion Greatly Reduces Plasma Concentrations of Nadolol in Healthy Subjects. Clin Pharmacol Ther 2014. [Epub ahead of print]. View abstract.
- Golden ED, Lam PY, Kardosh A, et al. Green tea polyphenols block the anticancer effects of bortezomib and other boronic acid-based proteasome inhibitors. Blood 2009;113:5927-37. View abstract.
- Phung OJ, Baker WL, Matthews LJ, et al. Effect of green tea catechins with or without caffeine on anthropometric measures: a systemic review and meta-analysis. Am J Clin Nutr 2010;91:73-81. View abstract.
- Savitz DA, Chan RL, Herring AH, et al. Caffeine and miscarriage risk. Epidemiology 2008;19:55-62. View abstract.
- Weng X, Odouli R, Li DK. Maternal caffeine consumption during pregnancy and the risk of miscarriage: a prospective cohort study. Am J Obstet Gynecol 2008;198:279.e1-8. View abstract.
- Kundu T, Dey S, Roy M, et al. Induction of apoptosis in human leukemia cells by black tea and its polyphenol theaflavin. Cancer Lett 2005;230:111-21. View abstract.
- Liu S, Lu H, Zhao Q, et al. Theaflavin derivatives in black tea and catechin derivatives in green tea inhibit HIV-1 entry by targeting gp41. Biochim Biophys Acta 2005;1723:270-81. View abstract.
- Yanagida A, Shoji A, Shibusawa Y, et al. Analytical separation of tea catechins and food-related polyphenols by high-speed counter-current chromatography. J Chromatogr A 2006;1112:195-201. View abstract.
- Taubert D, Roesen R, Schomig E. Effect of cocoa and tea intake on blood pressure: a meta-analysis. Arch Intern Med 2007;167:626-34. View abstract.
- Lorenz M, Jochmann N, von Krosigk A, et al. Addition of milk prevents vascular protective effects of tea. Eur Heart J 2007;28:219-23. View abstract.
- Correa A, Stolley A, Liu Y. Prenatal tea consumption and risks of anencephaly and spina bifida. Ann Epidemiol 2000;10:476-7. View abstract.
- Bradley Pharmaceuticals. Veregen Prescribing Information. October 2006.
- Katiyar SK, Mohan RR, Agarwal R, Mukhtar H. Protection against induction of mouse skin papillomas with low and high risk of conversion to malignancy by green tea polyphenols. Carcinogenesis 1997;18:497-502. View abstract.
- Jimenez-Saenz M, Martinez-Sanchez, MDC. Acute hepatitis associated with the use of green tea infusions. J Hepatol 2006;44:616-9. View abstract.
- Navarro-Peran E, Cabezas-Herrera J, Garcia-Canovas F, et al. The antifolate activity of tea catechins. Cancer Res 2005;65:2059-64. View abstract.
- Isbrucker RA, Edwards JA, Wolz E, et al. Safety studies on epigallocatechin gallate (EGCG) preparations. Part 3: teratogenicity and reproductive toxicity studies in rats. Food Chem Toxicol 2006;44:651-61. View abstract.
- Chu KO, Wang CC, Chu CY, et al. Pharmacokinetic studies of green tea catechins in maternal plasma and fetuses in rats. J Pharm Sci 2006;95:1372-81. View abstract.
- Kuriyama S, Shimazu T, Ohmori K, et al. Green tea consumption and mortality due to cardiovascular disease, cancer, and all-cause mortality. JAMA 2006;296:1255-65. View abstract.
- Wu AH, Tseng CC, Van Den Berg D, Yu MC. Tea intake, COMT genotype, and breast cancer in Asian-American women. Cancer Res 2003;63:7526-9. View abstract.
- Yuan JM, Koh WP, Sun CL, et al. Green tea intake, ACE gene polymorphism and breast cancer risk among Chinese women in Singapore. Carcinogenesis 2005;26:1389-94. View abstract.
- Donovan JL, Chavin KD, Devane CL, et al. Green tea (Camellia sinensis) extract does not alter cytochrome P450 3A4 or 2D6 activity in healthy volunteers. Drug Metab Dispos 2004;32:906-8. View abstract.
- Kovacs EM, Lejeune MP, Nijs I, Westerterp-Plantenga MS. Effects of green tea on weight maintenance after body-weight loss. Br J Nutr 2004;91:431-7. View abstract.
- Wu AH, Yu MC, Tseng CC, et al. Green tea and risk of breast cancer in Asian Americans. Int J Cancer 2003;106:574-9. View abstract.
- Suzuki Y, Tsubono Y, Nakaya N, et al. Green tea and the risk of breast cancer: pooled analysis of two prospective studies in Japan. Br J Cancer 2004;90:1361-3. View abstract.
- Iso H, Date C, Wakai K, et al; JACC Study Group. The relationship between green tea and total caffeine intake and risk for self-reported type 2 diabetes among Japanese adults. Ann Intern Med 2006;144:554-62. View abstract.
- Gloro R, Hourmand-Ollivier I, Mosquet B, et al. Fulminant hepatitis during self-medication with hydroalcoholic extract of green tea. Eur J Gastroenterol Hepatol 2005;17:1135-7. View abstract.
- Bonkovsky HL. Hepatotoxicity associated with supplements containing Chinese green tea (Camellia sinensis). Ann Intern Med 2006;144:68-71. View abstract.
- Henning M, Fajardo-Lira C, Lee HW, et al. Catechin content of 18 teas and a green tea extract supplement correlates with the antioxidant capacity. Nutr Cancer 2003;45:226-35. View abstract.
- Khokhar S, Magnusdottir SG. Total phenol, catechin, and caffeine contents of teas commonly consumed in the United kingdom. J Agric Food Chem 2002;50:565-70. View abstract.
- Jian L, Xie LP, Lee AH, Binns CW. Protective effect of green tea against prostate cancer: a case-control study in southeast China. Int J Cancer 2004;108:130-5. View abstract.
- Bettuzzi S, Brausi M, Rizzi F, et al. Chemoprevention of human prostate cancer by oral administration of green tea catechins in volunteers with high-grade prostate intraepithelial neoplasia: a preliminary report from a one-year proof-of-principle study. Cancer Res 2006;66:1234-40. View abstract.
- Robinson LE, Savani S, Battram DS, et al. Caffeine ingestion before an oral glucose tolerance test impairs blood glucose management in men with type 2 diabetes. J Nutr 2004;134:2528-33. View abstract.
- Lake CR, Rosenberg DB, Gallant S, et al. Phenylpropanolamine increases plasma caffeine levels. Clin Pharmacol Ther 1990;47:675-85. View abstract.
- Forrest WH Jr, Bellville JW, Brown BW Jr. The interaction of caffeine with pentobarbital as a nighttime hypnotic. Anesthesiology 1972;36:37-41. View abstract.
- Raaska K, Raitasuo V, Laitila J, Neuvonen PJ. Effect of caffeine-containing versus decaffeinated coffee on serum clozapine concentrations in hospitalised patients. Basic Clin Pharmacol Toxicol 2004;94:13-8. View abstract.
- Watson JM, Sherwin RS, Deary IJ, et al. Dissociation of augmented physiological, hormonal and cognitive responses to hypoglycaemia with sustained caffeine use. Clin Sci (Lond) 2003;104:447-54. View abstract.
- Winkelmayer WC, Stampfer MJ, Willett WC, Curhan GC. Habitual caffeine intake and the risk of hypertension in women. JAMA 2005;294:2330-5. View abstract.
- Juliano LM, Griffiths RR. A critical review of caffeine withdrawal: empirical validation of symptoms and signs, incidence, severity, and associated features. Psychopharmacology (Berl) 2004;176:1-29. View abstract.
- Leson CL, McGuigan MA, Bryson SM. Caffeine overdose in an adolescent male. J Toxicol Clin Toxicol 1988;26:407-15. View abstract.
- Benowitz NL, Osterloh J, Goldschlager N, et al. Massive catecholamine release from caffeine poisoning. JAMA 1982;248:1097-8. View abstract.
- Acheson KJ, Gremaud G, Meirim I, et al. Metabolic effects of caffeine in humans: lipid oxidation or futile cycling? Am J Clin Nutr 2004;79:40-6. View abstract.
- Scholey AB, Kennedy DO. Cognitive and physiological effects of an "energy drink:" an evaluation of the whole drink and of glucose, caffeine and herbal flavouring fractions. Psychopharmacology (Berl) 2004;176:320-30. View abstract.
- Haller CA, Benowitz NL, Jacob P 3rd. Hemodynamic effects of ephedra-free weight-loss supplements in humans. Am J Med 2005;118:998-1003.. View abstract.
- Larsson SC, Wolk A. Tea consumption and ovarian cancer risk in a population-based cohort. Arch Intern Med 2005;165:2683-6. View abstract.
- Schabath MB, Hernandez LM, Wu X, et al. Dietary phytoestrogens and lung cancer risk. JAMA 2005;294:1493-1504. View abstract.
- Seely D, Mills EJ, Wu P, et al. The effects of green tea consumption on incidence of breast cancer and recurrence of breast cancer: a systematic review and meta-analysis. Integr Cancer Ther 2005;4:144-55. View abstract.
- Son DJ, Cho MR, Jin YR, et al. Antiplatelet effect of green tea catechins: a possible mechanism through arachidonic acid pathway. Prostaglandins Leukot Essent Fatty Acids 2004;71:25-31. View abstract.
- Choi JH, Chai YM, Joo GJ, et al. Effects of green tea catechin on polymorphonuclear leukocyte 5'-lipoxygenase activity, leukotriene B4 synthesis, and renal damage in diabetic rats. Ann Nutr Metab 2004;48:151-5. View abstract.
- Mohseni H, Zaslau S, McFadden D, et al. COX-2 inhibition demonstrates potent anti-proliferative effects on bladder cancer in vitro. J Surg Res 2004;119:138-42 . View abstract.
- Gupta S, Saha B, Giri AK. Comparative antimutagenic and anticlastogenic effects of green tea and black tea: a review. Mutat Res 2002;512:37-65. View abstract.
- Yang YC, Lu FH, Wu JS, et al. The protective effect of habitual tea consumption on hypertension. Arch Intern Med 2004 26;164:1534-40. View abstract.
- Haqqi TM, Anthony DD, Gupta S, et al. Prevention of collagen-induced arthritis in mice by a polyphenolic fraction from green tea. Proc Natl Acad Sci U S A 1999;96:4524-9. View abstract.
- Adcocks C, Collin P, Buttle DJ. Catechins from green tea (Camellia sinensis) inhibit bovine and human cartilage proteoglycan and type II collagen degradation in vitro. J Nutr 2002;132:341-6. View abstract.
- Ahmed S, Rahman A, Hasnain A, et al. Green tea polyphenol epigallocatechin-3-gallate inhibits the IL-1 beta-induced activity and expression of cyclooxygenase-2 and nitric oxide synthase-2 in human chondrocytes. Free Radic Biol Med 2002;33:1097-105. View abstract.
- Petrie HJ, Chown SE, Belfie LM, et al. Caffeine ingestion increases the insulin response to an oral-glucose-tolerance test in obese men before and after weight loss. Am J Clin Nutr 2004;80:22-8. View abstract.
- Lane JD, Barkauskas CE, Surwit RS, Feinglos MN. Caffeine impairs glucose metabolism in type 2 diabetes. Diabetes Care 2004;27:2047-8. View abstract.
- Vinson JA, Teufel K, Wu N. Green and black teas inhibit atherosclerosis by lipid, antioxidant, and fibrinolytic mechanisms. J Agric Food Chem 2004;52:3661-5. View abstract.
- Zheng G, Sayama K, Okubo T, et al. Anti-obesity effects of three major components of green tea, catechins, caffeine and theanine, in mice. In Vivo 2004;18:55-62. View abstract.
- Sato J, Nakata H, Owada E, et al. Influence of usual intake of dietary caffeine on single-dose kinetics of theophylline in healthy human subjects. Eur J Clin Pharmacol 1993;44:295-8. View abstract.
- Cannon ME, Cooke CT, McCarthy JS. Caffeine-induced cardiac arrhythmia: an unrecognised danger of healthfood products. Med J Aust 2001;174:520-1. View abstract.
- Durrant KL. Known and hidden sources of caffeine in drug, food, and natural products. J Am Pharm Assoc 2002;42:625-37. View abstract.
- Beach CA, Mays DC, Guiler RC, et al. Inhibition of elimination of caffeine by disulfiram in normal subjects and recovering alcoholics. Clin Pharmacol Ther 1986;39:265-70. View abstract.
- Dews PB, O'Brien CP, Bergman J. Caffeine: behavioral effects of withdrawal and related issues. Food Chem Toxicol 2002;40:1257-61. View abstract.
- Holmgren P, Norden-Pettersson L, Ahlner J. Caffeine fatalities--four case reports. Forensic Sci Int 2004;139:71-3. View abstract.
- Chou T. Wake up and smell the coffee. Caffeine, coffee, and the medical consequences. West J Med 1992;157:544-53. View abstract.
- Howell LL, Coffin VL, Spealman RD. Behavioral and physiological effects of xanthines in nonhuman primates. Psychopharmacology (Berl) 1997;129:1-14. View abstract.
- Rakic V, Beilin LJ, Burke V. Effect of coffee and tea drinking on postprandial hypotension in older men and women. Clin Exp Pharmacol Physiol 1996;23:559-63. View abstract.
- Heseltine D, Dakkak M, woodhouse K, et al. The effect of caffeine on postprandial hypotension in the elderly. J Am Geriatr Soc 1991;39:160-4. View abstract.
- Castellanos FX, Rapoport JL. Effects of caffeine on development and behavior in infancy and childhood: a review of the published literature. Food Chem Toxicol 2002;40:1235-42. View abstract.
- Institute of Medicine. Caffeine for the Sustainment of Mental Task Performance: Formulations for Military Operations. Washington, DC: National Academy Press, 2001. Available at: http://books.nap.edu/books/0309082587/html/index.html.
- Zheng XM, Williams RC. Serum caffeine levels after 24-hour abstention: clinical implications on dipyridamole Tl myocardial perfusion imaging. J Nucl Med Technol 2002;30:123-7. View abstract.
- Aqel RA, Zoghbi GJ, Trimm JR, et al. Effect of caffeine administered intravenously on intracoronary-administered adenosine-induced coronary hemodynamics in patients with coronary artery disease. Am J Cardiol 2004;93:343-6. View abstract.
- Underwood DA. Which medications should be held before a pharmacologic or exercise stress test? Cleve Clin J Med 2002;69:449-50. View abstract.
- Smith A. Effects of caffeine on human behavior. Food Chem Toxicol 2002;40:1243-55. View abstract.
- Stanek EJ, Melko GP, Charland SL. Xanthine interference with dipyridamole-thallium-201 myocardial imaging. Pharmacother 1995;29:425-7. View abstract.
- Carrillo JA, Benitez J. Clinically significant pharmacokinetic interactions between dietary caffeine and medications. Clin Pharmacokinet 2000;39:127-53. View abstract.
- Wahllander A, Paumgartner G. Effect of ketoconazole and terbinafine on the pharmacokinetics of caffeine in healthy volunteers. Eur J Clin Pharmacol 1989;37:279-83. View abstract.
- Sanderink GJ, Bournique B, Stevens J, et al. Involvement of human CYP1A isoenzymes in the metabolism and drug interactions of riluzole in vitro. Pharmacol Exp Ther 1997;282:1465-72. View abstract.
- Brown NJ, Ryder D, Branch RA. A pharmacodynamic interaction between caffeine and phenylpropanolamine. Clin Pharmacol Ther 1991;50:363-71. View abstract.
- May DC, Jarboe CH, VanBakel AB, Williams WM. Effects of cimetidine on caffeine disposition in smokers and nonsmokers. Clin Pharmacol Ther 1982;31:656-61. View abstract.
- Nawrot P, Jordan S, Eastwood J, et al. Effects of caffeine on human health. Food Addit Contam 2003;20:1-30. View abstract.
- Jatoi A, Ellison N, Burch PA, et al. A phase II trial of green tea in the treatment of patients with androgen independent metastatic prostate carcinoma. Cancer 2003;97:1442-6.. View abstract.
- Shirai T, Hayakawa H, Akiyama J, et al. Food allergy to green tea. J Allergy Clin Immunol 2003;112:805-6. View abstract.
- Massey LK, Whiting SJ. Caffeine, urinary calcium, calcium metabolism and bone. J Nutr 1993;123:1611-4. View abstract.
- Infante S, Baeza ML, Calvo M, et al. Anaphylaxis due to caffeine. Allergy 2003;58:681-2. View abstract.
- Ahn WS, Yoo J, Huh SW, et al. Protective effects of green tea extracts (polyphenon E and EGCG) on human cervical lesions. Eur J Cancer Prev 2003;12:383-90. View abstract.
- Kemberling JK, Hampton JA, Keck RW, et al. Inhibition of bladder tumor growth by the green tea derivative epigallocatechin-3-gallate. J Urol 2003;170:773-6. View abstract.
- Maron DJ, Lu GP, Cai NS, et al. Cholesterol-lowering effect of a theaflavin-enriched green tea extract: a randomized controlled trial. Arch Intern Med 2003;163:1448-53.. View abstract.
- Nix D, Zelenitsky S, Symonds W, et al. The effect of fluconazole on the pharmacokinetics of caffeine in young and elderly subjects. Clin Pharmacol Ther 1992;51:183.
- Kockler DR, McCarthy MW, Lawson CL. Seizure activity and unresponsiveness after hydroxycut ingestion. Pharmacotherapy 2001;21:647-51.. View abstract.
- Grandjean AC, Reimers KJ, Bannick KE, Haven MC. The effect of caffeinated, non-caffeinated, caloric and non-caloric beverages on hydration. J Am Coll Nutr 2000;19:591-600.. View abstract.
- Dreher HM. The effect of caffeine reduction on sleep quality and well-being in persons with HIV. J Psychosom Res 2003;54:191-8.. View abstract.
- Massey LK. Is caffeine a risk factor for bone loss in the elderly? Am J Clin Nutr 2001;74:569-70. View abstract.
- Nehlig A, Debry G. Consequences on the newborn of chronic maternal consumption of coffee during gestation and lactation: a review. J Am Coll Nutr 1994;13:6-21.. View abstract.
- McGowan JD, Altman RE, Kanto WP Jr. Neonatal withdrawal symptoms after chronic maternal ingestion of caffeine. South Med J 1988;81:1092-4.. View abstract.
- Bara AI, Barley EA. Caffeine for asthma. Cochrane Database Syst Rev 2001;4:CD001112.. View abstract.
- Bracken MB, Triche EW, Belanger K, et al. Association of maternal caffeine consumption with decrements in fetal growth. Am J Epidemiol 2003;157:456-66.. View abstract.
- Temme EH, Van Hoydonck PG. Tea consumption and iron status. Eur J Clin Nutr 2002;56:379-86.. View abstract.
- Leung LK, Su Y, Chen R, et al. Theaflavins in black tea and catechins in green tea are equally effective antioxidants. J Nutr 2001;131:2248-51.. View abstract.
- de Maat MP, Pijl H, Kluft C, Princen HM. Consumption of black and green tea had no effect on inflammation, haemostasis and endothelial markers in smoking healthy individuals. Eur J Clin Nutr 2000;54:757-63.. View abstract.
- Hodgson JM, Croft KD, Mori TA, et al. Regular ingestion of tea does not inhibit in vivo lipid peroxidation in humans. J Nutr 2002;132:55-8.. View abstract.
- Locher R, Emmanuele L, Suter PM, et al. Green tea polyphenols inhibit human vascular smooth muscle cell proliferation stimulated by native low-density lipoprotein. Eur J Pharmacol 2002;434:1-7.. View abstract.
- Zhang M, Binns CW, Lee AH. Tea consumption and ovarian cancer risk: a case-control study in China. Cancer Epidemiol Biomarkers Prev 2002;11:713-8.. View abstract.
- Yu GP, Hsieh CC. Risk factors for stomach cancer: a population-based case-control study in Shanghai. Cancer Causes Control 1991;2:169-74.. View abstract.
- Ji BT, Chow WH, Yang G, et al. The influence of cigarette smoking, alcohol, and green tea consumption on the risk of carcinoma of the cardia and distal stomach in Shanghai, China. Cancer 1996;77:2449-57.. View abstract.
- Kono S, Ikeda M, Tokudome S, Kuratsune M. A case-control study of gastric cancer and diet in northern Kyushu, Japan. Jpn J Cancer Res 1988;79:1067-74.. View abstract.
- Choi YT, Jung CH, Lee SR, et al. The green tea polyphenol (-)-epigallocatechin gallate attenuates beta-amyloid-induced neurotoxicity in cultured hippocampal neurons. Life Sci 2001;70:603-14.. View abstract.
- Tajima K, Tominaga S. Dietary habits and gastro-intestinal cancers: a comparative case-control study of stomach and large intestinal cancers in Nagoya, Japan. Jpn J Cancer Res 1985;76:705-16.. View abstract.
- Inoue M, Tajima K, Hirose K, et al. Tea and coffee consumption and the risk of digestive tract cancers: data from a comparative case-referent study in Japan. Cancer Causes Control 1998;9:209-16.. View abstract.
- Horner NK, Lampe JW. Potential mechanisms of diet therapy for fibrocystic breast conditions show inadequate evidence of effectiveness. J Am Diet Assoc 2000;100:1368-80. View abstract.
- Zijp IM, Korver O, Tijburg LB. Effect of tea and other dietary factors on iron absorption. Crit Rev Food Sci Nutr 2000;40:371-98. View abstract.
- Setiawan VW, Zhang ZF, Yu GP, et al. Protective effect of green tea on the risks of chronic gastritis and stomach cancer. Int J Cancer 2001;92:600-4. View abstract.
- Bell DG, Jacobs I, Ellerington K. Effect of caffeine and ephedrine ingestion on anaerobic exercise performance. Med Sci Sports Exerc 2001;33:1399-403. View abstract.
- Haller CA, Jacob P 3rd, Benowitz NL. Pharmacology of ephedra alkaloids and caffeine after single-dose dietary supplement use. Clin Pharmacol Ther 2002;71:421-32. View abstract.
- Avisar R, Avisar E, Weinberger D. Effect of coffee consumption on intraocular pressure. Ann Pharmacother 2002;36:992-5.. View abstract.
- Peters U, Poole C, Arab L. Does tea affect cardiovascular disease? A meta-analysis. Am J Epidemiol 2001;154:495-503. View abstract.
- Mukamal KJ, Maclure M, Muller JE, et al. Tea consumption and mortality after acute myocardial infarction. Circulation 2002;105:2476-81. View abstract.
- Geleijnse JM, Launer LJ, van der Kuip DA, et al. Inverse association of tea and flavonoid intakes with incident myocardial infarction: the Rotterdam Study. Am J Clin Nutr 2002;75:880-6. View abstract.
- Chung LY, Cheung TC, Kong SK, et al. Induction of apoptosis by green tea catechins in human prostate cancer DU145 cells. Life Sci 2001;68:1207-14. View abstract.
- Pisters KM, Newman RA, Coldman B, et al. Phase I trial of oral green tea extract in adult patients with solid tumors. J Clin Oncol 2001;19:1830-8. View abstract.
- Wu CH, Yang YC, Yao WJ, et al. Epidemiological evidence of increased bone mineral density in habitual tea drinkers. Arch Intern Med 2002;162:1001-6. View abstract.
- Cronin JR. Green tea extract stokes thermogenesis: will it replace ephedra? Altern Comp Ther 2000;6:296-300.
- Chantre P, Lairon D. Recent findings of green tea extract AR25 (Exolise) and its activity for the treatment of obesity. Phytomedicine 2002;9:3-8. View abstract.
- Shaw JC. Green tea polyphenols may be useful in the treatment of androgen-mediated skin disorders. Arch Dermatol 2001;137:664. View abstract.
- Samman S, Sandstrom B, Toft MB, et al. Green tea or rosemary extract added to foods reduces nonheme-iron absorption. Am J Clin Nutr 2001;73:607-12. View abstract.
- Ferrini RL, Barrett-Connor E. Caffeine intake and endogenous sex steroid levels in postmenopausal women. The Rancho Bernardo Study. Am J Epidemiol 1996:144:642-4. View abstract.
- Ardlie NG, Glew G, Schultz BG, Schwartz CJ. Inhibition and reversal of platelet aggregation by methyl xanthines. Thromb Diath Haemorrh 1967;18:670-3. View abstract.
- Ali M, Afzal M. A potent inhibitor of thrombin stimulated platelet thromboxane formation from unprocessed tea. Prostaglandins Leukot Med 1987;27:9-13. View abstract.
- Sadzuka Y, Sugiyama T, Sonobe T. Efficacies of tea components on doxorubicin induced antitumor activity and reversal of multidrug resistance. Toxicol Lett 2000;114:155-62. View abstract.
- Krahwinkel T, Willershausen B. The effect of sugar-free green tea chew candies on the degree of inflammation of the gingiva. Eur J Med Res 2000;5:463-7. View abstract.
- Tsubono Y, Nishino Y, Komatsu S, et al. Green tea and the risk of gastric cancer in Japan. N Engl J Med 2001;344:632-6. View abstract.
- Haller CA, Benowitz NL. Adverse cardiovascular and central nervous system events associated with dietary supplements containing ephedra alkaloids. N Engl J Med 2000;343:1833-8. View abstract.
- Imai K. Nakachi K. Cross-sectional study of effects of drinking green tea on cardiovascular and liver diseases. BMJ 1995;310:693-6. View abstract.
- Sinclair CJ, Geiger JD. Caffeine use in sports. A pharmacological review. J Sports Med Phys Fitness 2000;40:71-9. View abstract.
- Katiyar SK, Ahmad N, Mukhtar H. Green Tea and Skin. Arch Dermatol 2000;136:989-94. View abstract.
- Heck AM, DeWitt BA, Lukes AL. Potential interactions between alternative therapies and warfarin. Am J Health Syst Pharm 2000;57:1221-7. View abstract.
- Hodgson JM, Puddey IB, Croft KD, et al. Acute effects of ingestion of black and green tea on lipoprotein oxidation. Am J Clin Nutr 2000;71:1103-7. View abstract.
- Leenen R, Roodenburg AJ, Tijburg LB, et al. A single dose of tea with or without milk increases plasma antioxidant activity in humans. Eur J Clin Nutr 2000;54:87-92. View abstract.
- Nemecz G. Green tea. US Pharm 2000;May:67-70.
- American Academy of Pediatrics. The transfer of drugs and other chemicals into human milk. Pediatrics 2001;108:776-89. View abstract.
- Lloyd T, Johnson-Rollings N, Eggli DF, et al. Bone status among postmenopausal women with different habitual caffeine intakes: a longitudinal investigation. J Am Coll Nutr 2000;19:256-61. View abstract.
- Watson JM, Jenkins EJ, Hamilton P, et al. Influence of caffeine on the frequency and perception of hypoglycemia in free-living patients with type 1 diabetes. Diabetes Care 2000;23:455-9. View abstract.
- Ross GW, Abbott RD, Petrovitch H, et al. Association of coffee and caffeine intake with the risk of parkinson disease. JAMA 2000;283:2674-9. View abstract.
- Hagg S, Spigset O, Mjorndal T, Dahlqvist R. Effect of caffeine on clozapine pharmacokinetics in healthy volunteers. Br J Clin Pharmacol 2000;49:59-63. View abstract.
- Electronic Code of Federal Regulations. Title 21. Part 182 -- Substances Generally Recognized As Safe. Available at: http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid= 786bafc6f6343634fbf79fcdca7061e1&rgn=div5&view= text&node=21:18.104.22.168.13&idno=21
- Williams MH, Branch JD. Creatine supplementation and exercise performance: an update. J Am Coll Nutr 1998;17:216-34. View abstract.
- Briggs GB, Freeman RK, Yaffe SJ. Drugs in Pregnancy and Lactation. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 1998.
- Hindmarch I, Quinlan PT, Moore KL, Parkin C. The effects of black tea and other beverages on aspects of cognition and psychomotor performance. Psychopharmacol 1998;139:230-8. View abstract.
- Durlach PJ. The effects of a low dose of caffeine on cognitive performance. Psychopharmacology (Berl) 1998;140:116-9. View abstract.
- Kaegi E. Unconventional therapies for cancer: 2. Green tea. The Task Force on Alternative Therapies of the Canadian Breast Cancer Research Initiative. CMAJ 1998;158:1033-5. View abstract.
- Lee IP, Kim YH, Kang MH, et al. Chemopreventive effect of green tea (Camellia sinensis) against cigarette smoke induced mutations in humans. J Cell Biochem Suppl 1997;27:68-75. View abstract.
- Li N, Sun Z, Han C, Chen J. The chemopreventive effects of tea on human oral precancerous mucosa lesions. Proc Soc Exp Biol Med 1999;220:218-24. View abstract.
- Klaunig JE, Xu Y, Han C, et al. The effect of tea consumption on oxidative stress in smokers and nonsmokers. Proc Soc Exp Biol Med 1999;220:249-54. View abstract.
- Taylor JR, Wilt VM. Probable antagonism of warfarin by green tea. Ann Pharmacother 1999;33:426-8. View abstract.
- Weisburger JH. Tea and health: the underlying mechanisms. Proc Soc Exp Biol Med 1999;220:271-5. View abstract.
- Stammler G, Volm M. Green tea catechins (EGCG and EGC) have modulating effects on the activity of doxorubicin in drug-resistant cell lines. Anticancer Drugs 1997;8:265-8. View abstract.
- Inoue M, Tajima K, Mizutani M, et al. Regular consumption of green tea and the risk of breast cancer recurrence: follow-up study from the Hospital-based Epidemiologic Research Program at Aichi Cancer Center (HERPACC), Japan. Cancer Lett 2001;167:175-82. View abstract.
- Kao YH, Hiipakka RA, Liao S. Modulation of endocrine systems and food intake by green tea epigallocatechin gallate. Endocrinology 2000;141:980-7. View abstract.
- FDA. Proposed rule: dietary supplements containing ephedrine alkaloids. Available at: www.verity.fda.gov (Accessed 25 January 2000).
- Dews PB, Curtis GL, Hanford KJ, O'Brien CP. The frequency of caffeine withdrawal in a population-based survey and in a controlled, blinded pilot experiment. J Clin Pharmacol 1999;39:1221-32. View abstract.
- Nurminen ML, Niittynen L, Korpela R, Vapaatalo H. Coffee, caffeine and blood pressure: a critical review. Eur J Clin Nutr 1999;53:831-9. View abstract.
- DiPiro JT, Talbert RL, Yee GC, et al; eds. Pharmacotherapy: A pathophysiologic approach. 4th ed. Stamford, CT: Appleton & Lange, 1999.
- Migliardi JR, Armellino JJ, Friedman M, et al. Caffeine as an analgesic adjuvant in tension headache. Clin Pharmacol Ther 1994;56:576-86. View abstract.
- Pollock BG, Wylie M, Stack JA, et al. Inhibition of caffeine metabolism by estrogen replacement therapy in postmenopausal women. J Clin Pharmacol 1999;39:936-40. View abstract.
- Wemple RD, Lamb DR, McKeever KH. Caffeine vs caffeine-free sports drinks: effects on urine production at rest and during prolonged exercise. Int J Sports Med 1997;18:40-6. View abstract.
- Stookey JD. The diuretic effects of alcohol and caffeine and total water intake misclassification. Eur J Epidemiol 1999;15:181-8. View abstract.
- Fernandes O, Sabharwal M, Smiley T, et al. Moderate to heavy caffeine consumption during pregnancy and relationship to spontaneous abortion and abnormal fetal growth: a meta-analysis. Reprod Toxicol 1998;12:435-44. View abstract.
- Eskenazi B. Caffeine—filtering the facts. N Engl J Med 1999;341:1688-9. View abstract.
- Klebanoff MA, Levine RJ, DerSimonian R, et al. Maternal serum paraxanthine, a caffeine metabolite, and the risk of spontaneous abortion. N Engl J Med 1999;341:1639-44. View abstract.
- The National Toxicology Program (NTP). Caffeine. Center for the Evaluation of Risks to Human Reproduction (CERHR). Available at: http://cerhr.niehs.nih.gov/common/caffeine.html.
- Rapuri PB, Gallagher JC, Kinyamu HK, Ryschon KL. Caffeine intake increases the rate of bone loss in elderly women and interacts with vitamin D receptor genotypes. Am J Clin Nutr 2001;74:694-700. View abstract.
- Chiu KM. Efficacy of calcium supplements on bone mass in postmenopausal women. J Gerontol A Biol Sci Med Sci 1999;54:M275-80. View abstract.
- Vandeberghe K, Gillis N, Van Leemputte M, et al. Caffeine counteracts the ergogenic action of muscle creatine loading. J Appl Physiol 1996;80:452-7. View abstract.
- Wallach J. Interpretation of Diagnostic Tests. A synopsis of Laboratory Medicine. Fifth ed; Boston, MA: Little Brown, 1992.
- Graham HN. Green tea composition, consumption, and polyphenol chemistry. Prev Med 1992;21:334-50. View abstract.
- Lou FQ, Zhang MF, Zhang XG, et al. A study on tea-pigment in prevention of atherosclerosis. Chin Med J (Engl) 1989;102:579-83. View abstract.
- Booth SL, Madabushi HT, Davidson KW, et al. Tea and coffee brews are not dietary sources of vitamin K-1 (phylloquinone). J Am Diet Assoc 1995;95:82-3. View abstract.
- Ohno Y, Aoki K, Obata K, et al. Case-control study of urinary bladder cancer in metropolitan Nagoya. Natl Cancer Inst Monogr 1985;69:229-34. View abstract.
- Wakai K, Ohno Y, Obata K. Prognostic significance of selected lifestyle factors in urinary bladder cancer. Jpn J Cancer Res 1993;84:1223-9. View abstract.
- Bushman JL. Green tea and cancer in humans: a review of the literature. Nutr Cancer 1998;31:151-9. View abstract.
- L'Allemain G. [Multiple actions of EGCG, the main component of green tea]. Bull Cancer 1999;86:721-4. View abstract.
- Cao Y, Cao R. Angiogenesis inhibited by drinking tea. Nature 1999;398:381. View abstract.
- Garbisa S, Biggin S, Cavallarin N, et al. Tumor invasion: molecular shears blunted by green tea. Nat Med 1999;5:1216. View abstract.
- Dulloo AG, Duret C, Rohrer D, et al. Efficacy of a green tea extract rich in catechin polyphenols and caffeine in increasing 24-h energy expenditure and fat oxidation in humans. Am J Clin Nutr 1999;70:1040-5. View abstract.
- Hodgson JM, Puddey IB, Burke V, et al. Effects on blood pressure of drinking green and black tea. J Hypertens 1999;17:457-63. View abstract.
- Wakabayashi K, Kono S, Shinchi K, et al. Habitual coffee consumption and blood pressure: A study of self-defense officials in Japan. Eur J Epidemiol 1998;14:669-73. View abstract.
- Elmets CA, Singh D, Tubesing K, et al. Cutaneous photoprotection from ultraviolet injury by green tea polyphenols. J Am Acad Dermatol 2001;44:425-32. View abstract.
- Vahedi K, Domingo V, Amarenco P, Bousser MG. Ischemic stroke in a sportsman who consumed MaHuang extract and creatine monohydrate for bodybuilding. J Neurol Neurosurg Psychiatr 2000;68:112-3. View abstract.
- Joeres R, Klinker H, Heusler H, et al. Influence of mexiletine on caffeine elimination. Pharmacol Ther 1987;33:163-9. View abstract.
- Ascherio A, Zhang SM, Hernan MA, et al. Prospective study of caffeine intake and risk of Parkinson's disease in men and women. Proceedings 125th Ann Mtg Am Neurological Assn. Boston, MA: 2000;Oct 15-18:42 (abstract 53).
- Mitscher LA, Mitscher LA, Jung M, Shankel D, et al. Chemoprotection: a review of the potential therapeutic antioxidant properties of green tea (Camellia sinensis) and certain of its constituents. Med Res Rev 1997;17:327-65. View abstract.
- Merhav H, Amitai Y, Palti H, Godfrey S. Tea drinking and microcytic anemia in infants. Am J Clin Nutr 1985;41:1210-3. View abstract.
- Jefferson JW. Lithium tremor and caffeine intake: two cases of drinking less and shaking more. J Clin Psychiatry 1988;49:72-3. View abstract.
- Mester R, Toren P, Mizrachi I, et al. Caffeine withdrawal increases lithium blood levels. Biol Psychiatry 1995;37:348-50. View abstract.
- Healy DP, Polk RE, Kanawati L, et al. Interaction between oral ciprofloxacin and caffeine in normal volunteers. Antimicrob Agents Chemother 1989;33:474-8. View abstract.
- Carbo M, Segura J, De la Torre R, et al. Effect of quinolones on caffeine disposition. Clin Pharmacol Ther 1989;45:234-40. View abstract.
- Harder S, Fuhr U, Staib AH, Wolff T. Ciprofloxacin-caffeine: a drug interaction established using in vivo and in vitro investigations. Am J Med 1989;87:89S-91S. View abstract.
- Foster S, Duke JA. Eastern/Central Medicinal Plants. New York, NY: Houghton Mifflin Co., 1990.
- Hertog MGL, Sweetnam PM, Fehily AM, et al. Antioxidant flavonols and ischemic heart disease in a Welsh population of men: the Caerphilly Study. Am J Clin Nutr 1997;65:1489-94. View abstract.
- Kubota K, Sakurai T, Nakazato K, et al. [Effect of green tea on iron absorption in elderly patients with iron deficiency anemia]. Nippon Ronen Igakkai Zasshi 1990;27:555-8. View abstract.
- McKevoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
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