Omeprazole is a commonly used drug to inhibit gastric acid secretion and should be taken according to the condition, there is no such thing as four kinds of people who are not suitable for taking omeprazole. Omeprazole is a proton pump inhibitor, which acts on the wall cells of the gastric mucosa, inhibits the activity of the proton pump, blocks the secretion of gastric acid, and reduces a large amount of gastric acid in the gastric juice. Clinically, it is generally used for the treatment of diseases caused by excessive secretion of gastric acid or gastric acid reflux, such as gastroesophageal reflux disease, gastritis, gastric ulcer, gastric polyp, gastric tumor and so on. Some patients with gastric diseases may be accompanied by decreased function of gastric wall cells, glandular atrophy, decreased gastric acid secretion, at this time it is not suitable for oral omeprazole, which may aggravate the condition. Long-term oral omeprazole may cause vitamin B12 deficiency, intestinal pheochromocytosis and other adverse reactions, omeprazole oral should be under the guidance of a doctor, rational use, do not blindly take the drug, so as not to cause irreversible damage.