Bad breath may be caused by personal oral hygiene, gingivitis, gastric ulcers and other diseases, and can be improved by daily care and medication to improve the symptoms of bad breath. 1. Personal oral hygiene: get up in the morning and before going to bed did not develop a good habit of brushing teeth, brushing the teeth in a non-standardized way, easy to make food residues left on the surface of the teeth to breed bacteria, triggering bad breath. Normally, you should pay attention to oral hygiene, insist on brushing your teeth at least twice a day and drink more water to improve the symptoms of bad breath. 2. gingivitis: plaque or tartar will secrete harmful substances after metabolic decomposition of the gums caused by stimulation, which in turn triggered gingivitis, the symptoms of bad breath, you can use hydrogen peroxide mouthwash rinse, to improve the bad breath, but also need to carry out periodontal scaling, so as not to aggravate the inflammation of the gums. 3. gastric ulcer: gastric ulcer is mainly caused by the infection of Helicobacter pylori, which may or may not lead to bad taste in the mouth, triggering bad breath. You can use drugs such as amoxicillin to reduce the local inflammation of the stomach lining and reduce the H. pylori bacteria in the stomach. There are many other causes of bad breath, if the bad breath is more serious, it is recommended to go to the hospital to improve the relevant examination, and follow the doctor’s instructions for treatment.