Bad Breath or Halitosis is the term used to describe unpleasant smell exhaled in breathing. There are different types of Halitosis. Transient bad breath is very common and is caused due to oral dryness, stress, hunger, eating foods containing garlic and onions, smoking and poor oral hygiene. Morning breath and chronic bad breath are the other types. The latter affects 25% of the population at different levels. This condition is caused by the overpopulation of certain types of oral bacteria like streptococcus mutans, and requires special treatment. Fetor hepaticus is a type of bad breath caused by chronic liver failure.

There are different factors that affect the mouth and cause bad breath. Dental decay, gum disease, food stagnation between the teeth, dry mouth, excessive bacterial activity on the tongue, throat or tonsil infection and catarrh are some of them. The factors that affect the airways and cause bad breath are sinusitis, polyps, dryness, foreign body, mucus flow, bronchitis, pneumonia and bronchiectasis. Food stagnation, gastric and blood influx cause bad breath. Bad breath can also be a sign of a significant general health problem.

Over 400 types of bacteria are found in the average mouth. Huge quantities of these naturally-occurring bacteria are often found on the posterior of the tongue, where they are undisturbed by normal activity. The surface of the tongue dorsum being rough provides an ideal habitat for anaerobic bacteria, which flourish under a continually-forming tongue coating of food debris, dead cells, and thousands of bacteria, both living and dead. The anaerobic respiration of such bacteria can yield either the putrescent smell of polyamines, or the "rotten egg" smell of volatile sulfur compounds (VSCs). When these compounds mix with mouth air, they produce unpleasant breath.

You can prevent bad breath by maintaining a high level of oral and dental hygiene. It requires cleaning of tongue right to the back, using a mouthwash recommended by the dentist, drinking plenty of fluids and avoiding too much of coffee. Sugar-free gum and fresh and fibrous vegetables are taken to prevent bad breath. Tobacco products should be avoided. Brush twice a day with fluoride toothpaste to remove food debris. Mouthwashes and mints give temporary release since they mask the smell for a few minutes. Rinses containing chloehexidine, zinc gluconate or chlorine dioxide should be used. Alcohol, being a drying agent, should be avoided.

Maintaining a proper water level in the body by drinking several glasses of water a day is important to prevent your mouth from being dry. Adding lemon juice to the water before drinking is considered beneficial. Eating yogurt, drinking green tea or chewing cinnamon or sugarless cinnamon gum can reduce bad breath.