Have you heard or read that there is a stomach bacteria that causes bad breath? It has been suggested that one of the causes of bad breath is Helicobacter pylori, the organism that causes stomach ulcers and ulcers in the duodenum. There is a laboratory test for the presence of this organism that detects a substance in the expelled breath, however, the test is not terribly reliable, and there is no firm evidence that H. pylori causes a significant unpleasant odor on the breath that others can detect.
In fact, in most cases, stomach breath doesn't really exist, unless you include the air that is expelled with a belch; odors due to belching are more likely to be associated with food than with bacteria. When we breathe out, the air that is expelled comes from the lungs, out through the throat, to the mouth and nose. It is not coming from the stomach. It's unlikely, then, that there is a stomach bacteria that causes bad breath.
Bad breath from the stomach is generally not much of an issue. Few bacteria can live in the stomach because of the very acid conditions there. (One of the functions of this acid environment is to kill ingested bacteria!) When air comes from the stomach breath may smell of onions, garlic, or other strong food odors, or even more unpleasant things if the person is ill, but these situations will be temporary. Rather than being in the stomach bacteria that causes bad breath colonize the mouth.
Rarely, a condition other than stomach bacteria causes bad breath that seems to come from lower down in the body. Some cancers can cause this and conditions such as liver or kidney disease cause stomach breath or odors from the lungs. These conditions are not trivial, so if you or someone you know has persistent bad breath from the stomach, or at least from beyond the mouth, a physician should be consulted for a professional opinion.
If you're still concerned about a stomach bacteria that causes bad breath, and you think you may have an ulcer or other health problem, discuss your concerns with your doctor as well. Bad breath from stomach conditions, if it is real in your case, should be diagnosed and treated.
Odor DetectR. Drysdale is a freelance writer with more than 25 years experience as a health care professional. She is a contributing editor to Causes of Bad Breath, a blog dedicated to the treatment of bad breath.