Bad breath is usually caused by oral bacteriaThe most common cause of halitosis is the anaerobic bacteria that live in a person's mouth.
For the majority of people (85 to 90% of those who have bad breath [halitosis]), the single most frequent
http://www.animated-teeth.com/bad_breath/t3_causes...
Causes There are a number of causes of bad breath, foremost among them being bacteria in the mouth, stomach and intestinal disturbances, bowel sluggishness, sinus or throat infections, and tobacco and alcoho
http://www.health911.com/remedies/rem_badbr.htm