Also termed as "feter aris" or "feter ex ere". It is defined as an unusual foul or offensive odor emanating form the oral cavity.

Origin - May be either local or extra-oral.

Local source of mouth odors - Detention of odoriferous food particles on the tooth surfaces, coated tongue, acute necrotizing gingivitis, dehydration states, caries, artificial dentures, smoker's breath, healing/extraction wounds.

Extra-oral/remote sources

1. Odors from adjacent structures associated with rhinitis, sinusitis or tonsillitis
2. Odors from pathologic conditions of the lungs and bronchi.
3. Odors excreted via lungs which are caused by aromatic substances in the blood stream.

Some disorders will produce specific, characteristic odors to the breath.

A fruity odor to the breath occurs as the body attempts to get rid of excess acetone through the breathing. This is a characteristic sign of ketoacidosis, which may occur in diabetes, and is a potentially life-threatening condition.

A fecal odor to the breath (the breath 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 nasogastric tube (a tube placed through the nose or mouth to the stomach to drain the stomach contents) in place.

The breath may have an ammonia-like odor (also described as urine-like or "fishy") in people with chronic kidney failure.

Diseases that may be associated with breath odor (not presented in order of likelihood -- some are extremely unlikely):

• Acute necrotizing ulcerative gingivitis
• Acute necrotizing ulcerative mucositis
• Acute renal failure
• Bowel obstruction (can cause breath to smell like feces)
• Bronchiectasis
• Chronic renal failure (can cause breath to smell like ammonia)
• Diabetes (fruity or sweet chemical smell with ketoacidosis)
• Esophageal cancer
• Gastric carcinoma
• Gastrojejunocolic fistula (fruity-smelling breath)
• Hepatic encephalopathy
• Diabetic ketoacidosis
• Lung abscess
• Ozena, or atrophic rhinitis
• Periodontal disease
• Pharyngitis
• Zenker's diverticulum

The physical examination will include a thorough examination of the mouth and the nose. A throat culture may be taken if the patient has a sore throat or mouth sores.

In rare cases, diagnostic tests that may be performed include:

• Endoscopy (EGD)
• X-ray of the abdomen
• X-ray of the chest
• Blood tests to screen for diabetes or renal failure

Antibiotics may be prescribed for some conditions. For an object in the nose, the doctor will use an instrument to remove it.

What is the treatment for bad breath?
If your dentist determines that your mouth is healthy and that the odor is not of oral origin, you may be referred to your family physician or to a specialist to determine the cause of the odor and for treatment. Of course, if the odor is of oral origin, as it is in the majority of cases, your dentist can treat the cause of the problem.

If the odor is due to periodontal (gum) disease, your general dentist can either treat the disease or refer you to a periodontist, a specialist in treating gum tissues. Periodontal (gum) disease can cause gum tissues to pull away from the teeth and form pockets. When these pockets are deep, only a professional periodontal cleaning can remove the bacteria and plaque that accumulate. Sometimes more extensive treatment is necessary.

If you have extensive build-up of plaque, an invisible layer of bacteria, your dentist may recommend using a special antimicrobial mouthrinse. Your dentist may also recommend that when you brush your teeth, you also brush your tongue to remove excess plaque.