Inclusion Criteria:  Diagnosis or suspected diagnosis of one of the following common digestive mucosal diseases: gastritis, gastric cancer, colorectal polyps, bowel cancer Written informed consent  Exclusion Criteria:  Patients with cardiovascular and cerebrovascular diseases, or patients with severe impairment of liver, kidney and hematopoietic system Mental patients Hemorrhagic diseases Platelet count < 50 × 10 ^ 9 / L Allergic constitution unable to tolerate or cooperate with endoscopy Patients with serious complications, such as intestinal obstruction, intestinal perforation, toxic colonic dilatation, colorectal cancer, etc. Pregnant or lactating women