Breath odor is the scent of the air you breathe out of your mouth. Unpleasant breath odor is commonly called bad breath.
Some disorders will produce distinct breath odors.
Bad breath related to poor oral hygiene is most common and caused by release of sulphur compounds by bacteria in the mouth.
A fruity odor to the breath is a sign of ketoacidosis, which may occur in diabetes. It is a potentially life-threatening condition.
Breath that smells like feces can occur with prolonged vomiting, especially when there is a bowel obstruction. It may also occur temporarily if a person has a tube placed through the nose or mouth to the stomach to drain the stomach contents (nasogastric tube) in place.
The breath may have an ammonia-like odor (also described as urine-like or "fishy") in people with chronic kidney failure.
Bad breath can be caused by:
- Abscessed tooth
- Eating certain foods, such as cabbage, garlic, or raw onions
- Consumption of coffee and not well pH-balanced diet
- Object stuck in the nose (usually happens in kids); often a white, yellow, or bloody discharge from one nostril
- Gum disease (gingivitis, gingivostomatitis)
- Impacted tooth
- Lung infection
- Poor dental hygiene
- Throat infection
- Tobacco smoking
- Vitamin supplements (especially in large doses)
- Use of certain medications, including insulin shots, triamterene, and paraldehyde
Diseases that may be associated with breath odor:
- Acute necrotizing ulcerative gingivitis
- Acute necrotizing ulcerative mucositis
- Acute renal failure
- Bowel obstruction (can cause breath to smell like feces)
- Chronic kidney failure (can cause breath to smell like ammonia)
- Diabetes (fruity or sweet chemical smell associated with ketoacidosis)
- Esophageal cancer
- Gastric carcinoma
- Gastrojejunocolic fistula (fruity-smelling breath)
- Hepatic encephalopathy
- Diabetic ketoacidosis
- Lung abscess
- Ozena, or atrophic rhinitis
- Periodontal disease
- Zenker's diverticulum
Use proper dental hygiene, especially flossing. Remember that mouthwashes are not effective in treating the underlying problem.
Fresh parsley or a strong mint is often an effective way to fight temporary bad breath. Avoid smoking.
Otherwise, follow your doctor's instructions to treat any underlying cause of bad breath.
When to Contact a Medical Professional
- Breath odor does not go away and there is not an obvious cause (such as smoking or eating odor-causing foods).
- You have breath odor and signs of a respiratory infection, such as fever, cough, or face pain with discharge from the nose.
What to Expect at Your Office Visit
Your doctor will take a medical history and perform a physical exam.
You may be asked the following medical history questions:
- Is there a specific odor (such as fish, ammonia, fruit, feces, or alcohol)?
- Have you recently eaten a spicy meal, garlic, cabbage, or other "odorous" food?
- Do you take vitamin supplements?
- Do you smoke?
- What home care and oral hygiene measures have you tried? How effective are they?
- Is there a recent sore throat, sinus infection, tooth abscess, or other illness?
- What other symptoms do you have?
The physical exam will include a thorough inspection of the mouth and the nose. A throat culture may be taken if you have a sore throat or mouth sores.
In rare cases, diagnostic tests that may be performed include:
- Blood tests to screen for diabetes or kidney failure
- Endoscopy (EGD)
- X-ray of the abdomen
- X-ray of the chest
Antibiotics may be prescribed for some conditions. For an object in the nose, the doctor will use an instrument to remove it.
Bad breath; Halitosis
Stein PS, Miller CS, Fowler CB. Oral disorders. In: Ham RJ, Sloane PD, Warshaw GA, Bernard MA, Potter JF, Flaherty E, eds.Primary Care Geriatrics: A Case-Based Approach
Murr AH. Approach to the patient with nose, sinus, and ear disorders. In: Goldman L, Schafer AI, eds.Cecil Medicine
Update Date 2/25/2014
Updated by: Ilona Fotek, DMD, MS, Palm Beach Prosthodontics Dental Associates, West Palm Beach, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.