Halitosis refers to the presence of foul odor of saliva, which usually suggests the phenomenon of halitosis, generally first consider whether the consumption of heavy flavored food, such as garlic, onions, leeks, etc., or smoked without timely mouth rinsing and the resulting odor, generally by timely rinsing, brushing or avoiding such food can reduce the occurrence of halitosis. In addition, it is mainly divided into orogenic halitosis, non-oral halitosis and mental halitosis: 1, orogenic halitosis: mainly caused by periodontal disease and dental caries, food residues in the cracks of teeth and dental caries continue to accumulate, with bacterial reproduction is easy to produce bad odor. It may also be due to necrotizing stomatitis and noma which can produce corrosive odor, as well as oral candidiasis and oral dryness which can lead to bad breath. Need to solve the disease in the oral cavity, can follow the medical advice to use antibiotics for treatment, for caries can be extracted if necessary; 2, non-stomatogenic halitosis: mainly due to digestive system diseases, the presence of inflammation or other lesions will lead to bad breath. In addition, liver and kidney failure, or blood disease, diabetes, vitamin deficiency, and heavy metal poisoning will lead to bad breath. Treatment is needed for the cause, and after the primary cause is treated, the bad breath will be reduced; 3. Psychogenic halitosis: mainly manifested as delusional halitosis, the patient is conscious of halitosis, but the cause of halitosis is not identified in the clinic. Need to improve the patient’s mental problems in order to get relief, pay attention to relieve tension, you can also seek psychological counseling with a psychiatrist. In addition, it is also necessary to pay attention to oral hygiene, while brushing the teeth can be cleaned tongue, and the use of mouthwash containing antibacterial effect, such as chlorhexidine combined with ciprochlor for mouth rinsing, can effectively reduce the symptoms of bad breath.