What is it?
Blessed thistle is a plant. People use the flowering tops, leaves, and upper stems to make medicine. Blessed thistle was commonly used during the Middle Ages to treat the bubonic plague and as a tonic for monks.
Today, blessed thistle is prepared as a tea and used for loss of appetite and indigestion; and to treat colds, cough, fever, bacterial infections, and diarrhea. It is also used as a diuretic for increasing urine output, and for promoting the flow of breast milk in new mothers.
Some people soak gauze in blessed thistle and apply it to the skin for treating boils, wounds, and ulcers.
In manufacturing, blessed thistle is used as a flavoring in alcoholic beverages.
Don’t confuse blessed thistle with milk thistle (Silybum marianum).
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 BLESSED THISTLE are as follows:
Insufficient evidence to rate effectiveness for...
- Promoting milk flow in breast-feeding mothers.
- Promoting urine flow.
- Other conditions.
More evidence is needed to rate the effectiveness of blessed thistle for these uses.
Blessed thistle contains tannins which might help diarrhea, coughs, and inflammation. However, there isn't enough information to know how well blessed thistle might work for many of its uses.
Blessed thistle might be safe for most people. In high doses, such as more than 5 grams per cup of tea, blessed thistle can cause stomach irritation and vomiting.
Special precautions & warnings:
Pregnancy and breast-feeding: Don’t take blessed thistle by mouth if you are pregnant. There is some evidence that it might not be safe during pregnancy. It’s also best to avoid blessed thistle if you are breast-feeding. Not enough is known about the safety of this product.
Intestinal problems, such as infections, Crohn's disease, and other inflammatory conditions: Don’t take blessed thistle if you have any of these conditions. It might irritate the stomach and intestines.
Allergy to ragweed and related plants: Blessed thistle may cause an allergic reaction in people who are sensitive to the Asteraceae/Compositae family. Members of this family include ragweed, chrysanthemums, marigolds, daisies, and many others. If you have allergies, be sure to check with your healthcare provider before taking blessed thistle.
Be watchful with this combination.
Antacids are used to decrease stomach acid. Blessed thistle may increase stomach acid. By increasing stomach acid, blessed thistle might decrease the effectiveness of antacids.
Some antacids include calcium carbonate (Tums, others), dihydroxyaluminum sodium carbonate (Rolaids, others), magaldrate (Riopan), magnesium sulfate (Bilagog), aluminum hydroxide (Amphojel), and others.
Medications that decrease stomach acid (H2-blockers)
Blessed thistle might increase stomach acid. By increasing stomach acid, blessed thistle might decrease the effectiveness of some medications that decrease stomach acid, called H2-blockers.
Some medications that decrease stomach acid include cimetidine (Tagamet), ranitidine (Zantac), nizatidine (Axid), and famotidine (Pepcid).
Medications that decrease stomach acid (Proton pump inhibitors)
Blessed thistle might increase stomach acid. By increasing stomach acid, blessed thistle might decrease the effectiveness of medications that are used to decrease stomach acid, called proton pump inhibitors.
Some medications that decrease stomach acid include omeprazole (Prilosec), lansoprazole (Prevacid), rabeprazole (Aciphex), pantoprazole (Protonix), and esomeprazole (Nexium).
There are no known interactions with herbs and supplements.
There are no known interactions with foods.
The appropriate dose of blessed thistle depends on several factors such as the user’s age, health, and several other conditions. At this time there is not enough scientific information to determine an appropriate range of doses for blessed thistle. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult your pharmacist or physician or other healthcare professional before using.
Carbenia Benedicta, Cardo Bendito, Cardo Santo, Carduus, Carduus Benedictus, Chardon Béni, Chardon Bénit, Chardon Marbré, Cnici Benedicti Herba, Cnicus, Cnicus benedictus, Holy Thistle, Safran Sauvage, Spotted Thistle, St. Benedict Thistle.
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 Blessed thistle page, please go to http://www.nlm.nih.gov/medlineplus/druginfo/natural/94.html.
- 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=21:22.214.171.124.13&idno=21
- Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
- McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
- Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics. 2nd ed. New York, NY: John Wiley & Sons, 1996.
- Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
Last reviewed - 04/03/2012
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