You should not eat within 6-8 hours before the gastroscopy examination. Food entering the stomach will not only affect the color of the gastric mucous membrane, but also the secretion of gastric acid, so gastroscopy examination after eating will affect the examination result. After eating food 1 night before the gastroscopy examination, you should stop any food intake, and should be fasted until the examination, so that you can observe the color of the gastric mucosa more clearly, and at the same time, you can extract part of the digestive fluid, and analyze the digestive fluid, which will give you a more accurate examination result. Once eating or drinking will cause some changes to the color of the digestive mucosa, and will also dilute the stomach acid leading to the analysis of digestive fluid results are affected. For 2-4 hours after the gastroscopy, the esophagus will be paralyzed, so food should not be eaten. After 4 hours, the anesthesia drug will be gradually metabolized, and then you can eat liquid or semi-liquid food.