It’s not sensational: clinical surveys show that 90% of bad breath originates from the tongue. Unfortunately, the uninformed use a toothbrush to brush the tongue, the effect is not good, only to transfer the bad breath causing bacteria to another place. Oral odor is divided into: 1, temporary bad breath: mainly related to garlic, onions and other foods and drinks. 2, chronic bad breath: related to bacteria and disease caused by. The main causes: 1, food; 2, bacteria: U.S. clinical surveys show that 90% of oral odor originated from the tongue, many people because of nasal secretions after the flow to the tongue, by the relevant bacterial decomposition to produce odor; 3, dry mouth: lack of self-cleaning mouth; 4, drugs; 5, dieting: dieters body will have ketosis, bad breath from the stomach; 6, smoking; 7, alcohol consumption; 8, other systemic diseases: tumors, diabetes, etc.