Halitosis caused by H. pylori infection has an ammonia odor and cannot be eliminated by cleaning the mouth with toothpaste. Usually, the four-phase therapy is used to treat H. pylori. 1. Characteristics of bad breath caused by H. pylori infection: bad breath is ammonia odor, mainly due to the urease enzyme produced by H. pylori to decompose urea, which produces ammonia and carbon dioxide in the stomach, and the bad taste in the mouth is similar to ammonia odor. And brushing teeth and other oral cleaning measures can not get rid of. 2. Treatment: H. pylori commonly used quadruple therapy. The main drug of quadruple therapy is an acid-suppressing drug + two antibiotics + a bismuth agent, such as: omeprazole + clarithromycin + amoxicillin + bismuth potassium citrate and so on. In addition to oral medication, patients usually need to pay attention to dietary adjustments, avoid eating spicy and stimulating foods as well as acidic foods. It is recommended that the occurrence of Helicobacter pylori infection, to the standardized hospital gastroenterology consultation, specific anti-infection medication program to prevent the abuse of antibiotic drugs.