Foul breath may be caused by eating heavy flavored food, unclean mouth and other physiological factors, pay attention to maintain oral hygiene can be. If caused by periodontitis, chronic gastritis, you need to take the right amount of drugs, surgical treatment. 1. Physiological factors: if you eat onions, garlic and other heavy flavored foods, may make the mouth appear temporary odor. In addition, do not brush your teeth in time or do not rinse your mouth after eating will make the mouth not clean, also easy to cause bad breath odor. These are physiological factors, you should pay attention to keep the mouth clean, eat less flavorful food to improve. 2. periodontitis: for gingivitis caused by bad breath can be used for periodontal treatment and antibacterial mouthwash rinses, such as 0.2% chlorhexidine, hydrogen peroxide solution. For gingival fibrous hyperplasia or gingival form has not been restored, can be gingivoplasty treatment. 3. Chronic gastritis: If the gastritis is caused by Helicobacter pylori infection, the patient will have the symptom of smelly breath. Patients need to be treated with quadruple therapy under the guidance of a doctor, i.e., treatment with proton pump inhibitors + two antibiotics + bismuth, commonly used drugs include omeprazole, metronidazole, clindamycin, bismuth potassium citrate and so on. For patients presenting with high-grade epithelial sarcoma of the stomach, gastroscopic mucosal resection and gastroscopic line mucosal dissection are required. Foul breath may also be caused by dental caries, periodontal abscess, oral cancer, gastric cancer, pyloric obstruction, lung abscess, bronchial dilatation, uremia, diabetes and other diseases. It is recommended that patients with bad breath exclude physiological factors, need to consult a doctor in time to check the cause of treatment. The use of drugs under the guidance of a doctor.