The side effects of Omeprazole Magnesium Enteric Coated Tablets include allergy, gastrointestinal reaction, liver function impairment, and atrophic gastritis. 1. Allergy: Omeprazole magnesium enteric-coated tablets belong to proton pump inhibitors, which can treat acid reflux, heartburn and other symptoms by inhibiting secretion. Some patients may have allergic side effects such as rash and itching. 2. Digestive tract reaction: Omeprazole magnesium enteric-coated tablets inhibit gastric acid secretion leading to a decrease in gastric acid, which may cause indigestion, vomiting, diarrhea, constipation, abdominal distension and other digestive tract side effects. 3. Liver function injury: when Omeprazole magnesium enteric-coated tablets are metabolized through the liver, it may lead to liver function injury, with elevation of liver function indexes such as alanine aminotransferase and glutamic oxalate aminotransferase. 4. Atrophic gastritis: after taking omeprazole magnesium enteric-coated tablets for a long time, the function of the wall cells to secrete gastric acid is inhibited for a long time, which may lead to the thinning of the gastric mucosa or even develop into atrophic gastritis. Because omeprazole magnesium enteric-coated tablets have certain side effects, it is not recommended to take on their own, it is recommended to go to the hospital to check the gastroscopy, Helicobacter pylori breath test and other items under the guidance of the doctor to take.