Long-term use of omeprazole may result in systemic adverse reactions (e.g., headache) as well as gastrointestinal adverse reactions (e.g., nausea, flatulence). Omeprazole is a commonly used proton pump inhibitor, which can inhibit the secretion of gastric acid and play a role in protecting the gastric mucosa, and can also alleviate the symptoms of heartburn and acid reflux caused by excessive gastric acid, which can be used in the treatment of gastric ulcers, duodenal ulcers and gastroesophageal reflux disease. 1. Systemic adverse reactions: headache and dizziness, fever and fatigue, fatigue and discomfort, skin rash, allergic reactions and other adverse reactions can occur when taking omeprazole. 2. Gastrointestinal adverse reactions: nausea and vomiting, abdominal pain and diarrhea, acid reflux and flatulence, constipation, pancreatitis and dry mouth stomatitis and other gastrointestinal symptoms can also occur after taking omeprazole. Omeprazole should be avoided in combination with clarithromycin, diazepam, phenytoin sodium, warfarin, nifedipine, digoxin, atazanavir and imidazole antifungal drugs such as ketoconazole. It should be used with caution by those who are allergic to the drug, pregnant women and nursing mothers. It is recommended to use Omeprazole under the guidance of a doctor.