Bad breath means bad odor in the mouth, which is a foul odor emanating from the mouth, nose, throat, and other parts. There are many causes of halitosis, which need to be treated according to the specific cause. 1, physiological halitosis: mainly caused by smoking, drinking, eating certain irritating foods (such as onions and garlic), staying up late, etc., without medication, improve the bad habits can be alleviated. 2, pathological halitosis: mainly including oral diseases (dental caries, periodontal disease, gingivitis, etc.), gastrointestinal diseases (peptic ulcer, gastritis, etc.), respiratory diseases (pharyngitis, tonsillitis, etc.), etc., taking certain drugs such as chemotherapy drugs, sedative drugs, etc. will also cause bad breath. Treatment of pathological halitosis requires active treatment of the primary cause. Oral antibiotics such as metronidazole, penicillin V potassium tablets and amoxicillin can be taken, as well as digestive drugs such as dry yeast tablets, multi-enzyme tablets, lactase, stomachic tablets, etc. Oral drugs to promote gastric emptying such as domperidone can also be taken, and some traditional Chinese medicines such as Baohe pill, Hovenia Guodao pill and Qinggong San can improve the symptoms of bad breath. (The specific drugs mentioned in the article should be prescribed according to the specialist’s interview.) . Therefore, bad breath should be treated according to different etiologies. Patients are advised to consult specialist clinics such as stomatology, gastroenterology and respiratory medicine to clarify the cause of bad breath and treat it symptomatically.