Omeprazole is generally effective and has a strong and long-lasting effect of inhibiting gastric acid secretion. Omeprazole is a proton pump inhibitor with an inhibitory effect on gastric acid secretion and is indicated for chronic gastritis, peptic ulcer, reflux esophagitis and gastrinoma. It has a strong and long-lasting inhibitory effect on gastric acid secretion caused by various reasons. Common adverse reactions to this drug are diarrhea, heart, abdominal pain, bloating, constipation, headache, and possibly increased serum aminotransferase, rash, vertigo, drowsiness, and insomnia. It is contraindicated for those who are allergic to the product and those with severe renal insufficiency. It should also be noted that when treating gastric ulcers, the possibility of ulcerative gastric cancer should be ruled out first, because the use of this drug can reduce its symptoms, which may lead to a delay in the condition. Omeprazole should be used under the guidance of a doctor and should not be used on its own.