Clinically, by doing gastroscopy, lesions in the esophagus, stomach, duodenum bulb and descending part such as gastritis, gastric ulcer, duodenal ulcer, gastric cancer, etc. can be seen. A colonoscopy can be done to observe lesions in the intestines such as intestinal polyps, ulcerative colitis, and intestinal tumors. Gastroscopy is through the mouth into the esophagus, stomach, and reach the duodenum. It can see lesions in the bulbous and descending parts of the esophagus, stomach, and duodenum. Such as esophagitis, reflux esophagitis, esophageal tumors, ulcers of the esophagus, but also can see chronic gastritis, chronic atrophic gastritis, peptic ulcer, gastric polyps and gastric tumors and other lesions. Enteroscopy is entered through the anus and reaches the ileocecal valve. It is able to visualize the digestive tract, such as the presence of mucosal inflammation in the mucosa of the ascending colon, transverse colon, descending colon, and sigmoid colon, as well as intestinal polyps, ulcerative colitis, intestinal tumors, and diseases such as gastrointestinal bleeding. Before doing gastroenteroscopy, routine examination should be carried out first, and fasting and water should be prohibited before the examination. If there is any obvious discomfort during the examination, the doctor should be informed in time.