Drugs used to treat Helicobacter pylori include antibiotics, bismuth, and proton pump inhibitors. Side effects include gastrointestinal reactions, skin allergies, liver and kidney impairment, digestive disorders, and nervous system discomfort. 1. Antibiotic side effects: allergic rash, nausea, vomiting, diarrhea, loss of appetite, liver and kidney function damage and other adverse reactions can occur. 2. Bismuth side effects: nausea, vomiting, diarrhea, constipation and other adverse reactions may occur. 3. Proton pump inhibitor side effects: adverse reactions such as abdominal pain, bloating, nausea and vomiting, constipation, itching of the skin, dizziness, headache and dry mouth may occur. When taking these medications for H. pylori, be sure to take them under the guidance of your doctor in strict accordance with medical advice.