Stomach pain after vaccination may be due to gastritis, peptic ulcer and other factors, it is recommended to go to the hospital in time for examination and then take treatment according to the actual condition. Adverse reactions such as headache, dizziness, fatigue, pain at the injection site, and fever may occur after vaccination, but usually not stomach pain. Gastritis is usually caused by the secretion of a large amount of gastric acid by the stomach, which causes the phenomenon of stomach pain. Gastritis may also cause epigastric pain, abdominal distension, vomiting, acid reflux and other symptoms, which can be treated with medicines such as colloidal bismuth pectin capsules under the guidance of a doctor. Peptic ulcer is generally due to the peptic ulcer will promote the secretion of gastric acid to stimulate the gastric mucosa, causing the phenomenon of stomach pain. Peptic ulcer may appear acid reflux and other in, can use magnesium plus aluminum chewable tablets, omeprazole magnesium enteric-coated tablets and other drugs to treat. In daily life, attention should be paid to light diet and avoid strenuous exercise.