Most of the people infected with H. pylori have no obvious symptoms, and a few of them may have localized oral symptoms, epigastric discomfort, and gastrointestinal symptoms related to chronic gastritis. 1. Localized oral symptoms: unexplained bad breath. This can be improved by brushing teeth on time, using mouthwash and mouth fresheners. 2. Epigastric discomfort symptoms: mainly characterized by burning sensation behind the sternum and epigastrium, abdominal distension and discomfort, indigestion, also accompanied by acid reflux, heartburn, nausea, dry heaving and other discomforts. 3. Chronic gastritis-related gastrointestinal symptoms: chronic gastritis caused by Helicobacter pylori infection can cause a series of gastrointestinal symptoms such as fullness, acid reflux, hiccups, epigastric discomfort, nausea in the morning, etc. The further development of the disease can be anaemia, emaciation, and irregular abdominal pain and other symptoms. 4. In addition, H. pylori infection is also associated with some diseases other than digestive system, such as unexplained iron-deficiency anemia and thrombocytopenic purpura. Patients considering possible H. pylori infection are advised to seek timely and systematic diagnosis and treatment in order to avoid delaying their condition.