Inclusion Criteria:  Healthy people aged 30 years and planning to undergo colonoscopy; No history of gastrointestinal tumor; No ulcerative colitis or Crohn's disease; No gastrointestinal hemorrhagic disease; No history of gastrointestinal surgery, able to understand and willing to sign informed consent.  Exclusion Criteria:  Other serious diseases of the digestive tract, such as Crohn's disease ulcerative colitis; Patients with gastric and esophageal cancer and other malignant tumors; Unable to cooperate after communication; Subjects who have received radiotherapy and chemotherapy; Other researchers believe that they are not suitable for inclusion in this clinical trial, such as mental illness patients, critical patients, pregnant women, illiterate minors, cognitive impairment PI, students of the researcher, PI, affiliated research units of the co-investigator or employees of the sponsor, etc