Halitosis has many causes, including the following:
- Tobacco use. If you smoke, quit. Your bad breath may be due to other causes, too, but tobacco use is a guarantee of bad breath. If you are ready to quit, ask your doctor or dentist for advice and support.
- What you eat, or don't eat. Certain foods, such as garlic, contribute to bad breath, but only temporarily. Once they are absorbed into the bloodstream, the smell is expelled through the breath, but the odors remain until the body processes the food, so there’s no quick fix.
- Dry mouth. If your mouth is extremely dry, there is not enough saliva to wash away excess food particles and bacteria, which can cause an unpleasant smell if they build up on the teeth.
- Infections. Bad breath that seems to have no other cause may indicate an infection elsewhere in the body. If you have chronic bad breath and your dentist rules out any oral problems, see your doctor for an evaluation. Bad breath can be a sign of a range of conditions including respiratory tract infections, chronic sinusitis or bronchitis, diabetes, or liver and kidney problems, so it's important not to ignore the problem.
Article taken from: http://www.oralb.com/topics/GetRidOfBadBreath.aspx