Chief cause of bad breath: Bacteria

Chief cause of bad breath: Bacteria

Bad breath, also known as halitosis, may go far beyond a tinge of garlic or onions. Like other types of body odor (the aroma of sweaty feet, for instance), many forms of halitosis are the handiwork of bacteria. When the germs that live in the mouth break down food particles and other debris, they often foul the air with highly pungent chemicals.

For example, some types of oral bacteria produce hydrogen sulfide, the compound that lends the distinctive aroma to rotten eggs. Others produce methyl mercaptan, the chemical that makes feces smell like feces. Still others release putrescine, the aroma of rotten meat. As for the bacteria that produce cadaverine ... well, the name says it all.

Hydrogen sulfide, methyl mercaptan, and other compounds most often associated with bad breath are known in the dental trade as volatile sulfur compounds, or VSCs. ("Volatile" means "vaporous" and "effervescent," in this case.) These odor-causing compounds are produced by microbes that often live on bits of food that cling to the back of the tongue or get stuck between teeth. They can also thrive in the pockets between the gum and tooth, particularly if you have serious or even mild gum disease. Bacteria also tend to do extremely well in mouths that don't produce enough saliva to rinse away food particles. And if you have postnasal drip from chronic allergies or sinusitis, mucus can collect on the back of your tongue and provide rations for an army of bacteria.