Breath odor is unpleasant, distinctive, or offensive.

 

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.​