taken from:
http://health.msn.com/health-topics/oral-care/articlepage.aspx?cp-documentid=100230604>1=31029 Common causes of bad breath
Finding the source of your bad breath and taking measures to minimize or eliminate the odor is important for many reasons, including personal well-being and your social life. That said, the most common causes of bad breath include the following:
Insufficient brushing and flossing of the teeth
Peridontal disease caused by bacteria on the teeth that leads to the buildup of plaque
Infection of the throat or mouth
Xerostomia (dry mouth) caused by mouth breathing, certain medications, or a lack of or decreased production of saliva
Illness such as diabetes, chronic sinusitis, post-nasal drip, kidney disease, autoimmune disorders leading to dry mouth, gastroesophageal reflux disease, and others
High protein or severe calorie-restricting diets that can trigger the body into a state of "ketosis"
Smoking tobacco
Eating foods containing volatile compounds (garlic, onions) that are absorbed into the bloodstream
Poorly fitting dentures that can lead to trapped food particles and bacterial-related decay
A visit with your family dentist for a full dental and oral health examination would provide the expertise needed to diagnose and potentially eliminate the source of your problem. In the meantime, try these ideas to help minimize bad breath:
Brush your teeth at least twice per day in combination with daily flossing at the end of the day when you have finished eating and snacking.
Chew sugar-free gum containing xylitol to help increase the production of saliva and potentially decrease the growth of cavity-producing bacteria.
Avoid excess use of sugary products like soft drinks, fruit-juice drinks, and chewy candy; raisins and bananas are also culprits.
Avoid alcohol containing mouthwash as this may further dry the tissues in the mouth.
Eat foods like raw apples, celery, or carrots, which increase the production of saliva and naturally clean the teeth.
Reflux symptoms
While the cause of your mouth odor may very well be linked to gastroesophageal reflux disease, symptoms vary and are often dependent upon body type (whether you're thin or obese), social history (if you're a drinker or smoker) and personal medical concerns (such as diabetes or an autoimmune disorder). Additionally, if you eat just prior to going to bed or eat large meals instead of small ones, you might be contributing to your reflux symptoms. Food choices like chocolate, peppermint, fatty foods and caffeinated drinks can also play a role.
The following symptoms can occur with other medical conditions, including heart disease, and should be discussed with your doctor. But in general, gastroesophageal reflux disease symptoms include the following:
Heartburn or "indigestion" two or more times per week. This is often described as a burning sensation in the lower to mid-chest, and is more common after meals or when lying down.
Periods of belching, especially after eating
Difficulty in swallowing
Sour, "foul" or acid-like taste and odor in the mouth, especially after small amounts of liquid is regurgitated from the stomach, into the esophagus and sometimes, into the throat. While uncommon, this may lead to a wearing down of the tooth enamel due to the acidic nature of the reflux.
Sore throat and hoarseness
Dry cough and/or asthma like symptoms
Unexplained nausea