— Julie Frank, West Orange, New Jersey
A: You were right to start with your dentist. While pungent foods and spices like anchovies, onions, and garlic won't do your social life any favors, roughly 80 to 90 percent of all cases of chronically bad breath are traceable to oral troubles such as dental abscesses, gum disease, and poor oral hygiene. (Leave any kind of food particles between your teeth long enough, and the bacteria that live in your mouth will break them down, releasing smelly sulphur compounds.)
Since it sounds as though your dentist has done a thorough evaluation of your mouth, it may be time for a trip to your doctor. The first thing she or he should consider is any medications you might be taking. Forty-two different types of drugs, including antihistamines, antidepressants, sedatives, chemotherapy drugs, and muscle relaxants, have the side effect of drying out your mouth. Without the constant flush of saliva, smelly, dead cells from your gums and tongue can accumulate in your mouth. You can either change treatments or try strategies to increase saliva flow. (The remedies range from sugarless gum to prescription saliva substitutes.)
The next place to check is your sinuses—an infection there can also be a source of foul breath. Other causes can be a sore throat, infected lungs, kidney or liver failure, or uncontrolled diabetes.
If you're noticing a specific problem with alcohol and meat, the problem may originate in the liver or gallbladder, both of which play key roles in digesting alcohol, protein, and dietary fat. By working through a relatively short list of common causes, your doctor will help determine the source of your trouble—and with luck, an effective treatment.