The most common condition that causes bad breath is halitosis, which can be caused by a variety of reasons, the most common being infectious diseases of the oral periodontium, such as the most common periodontitis or dental caries, and something like acute necrotizing ulcerative gingivitis. All of these can be due to bacterial deposits, and some of the bacteria are Pseudomonas aeruginosa, which secrete sulfur-containing gases that have a distinctive odor, also known as malodor, and the phenomenon of halitosis occurs. The best treatment for this phenomenon is to go to a professional dentist, specific treatment for the disease, for dental caries should go to caries filling treatment. For periodontal disease should be periodontal scaling, that is, the usual scaling, the vast majority of patients after scaling, the symptoms of bad breath will be significantly relieved.