H. pylori killing drugs are usually not harmful to the body. The treatment of H. pylori often choose quadruple therapy, that is, a proton pump inhibitor + two antibiotics + a bismuth agent, common side effects include dizziness and headache, gastrointestinal reactions, intestinal flora disorders, liver and kidney function abnormalities and so on. 1. Dizziness and headache: Metronidazole and omeprazole can cause dizziness and headache. 2. Gastrointestinal reactions: Esomeprazole, metronidazole, clarithromycin, amoxicillin, etc., may induce gastrointestinal reactions, such as abdominal discomfort, nausea, vomiting, loss of appetite, etc. Antibiotics should be chosen to be taken after a meal to minimize gastrointestinal irritation. Bismuth may also cause black stools. 3. Dysbiosis of intestinal flora: the use of antibiotics may lead to dysbiosis of intestinal flora. 4. Abnormalities in liver and kidney function: Clarithromycin, esomeprazole and other drugs may lead to an increase in transaminases, serum creatinine concentration, etc. If the patient’s own liver and kidney function is poorer the effect may be greater. It is recommended to use the drug under the guidance of the doctor, not blindly self-medication. All of the above adverse reactions can be gradually recovered after stopping the drug, if the adverse reactions are serious or do not recover in time after stopping the drug, it is recommended to go to a regular hospital for consultation.