There are colonoscopies and electronic small colonoscopies. Colonoscopy mainly examines the small intestine, colon, rectum and anal canal, etc. Electronic small colonoscopy can observe the small intestine. 1. Colonoscopy: It can be used for the examination of colon, rectum, anal canal and other parts of the colon, colonoscopy can directly observe the inner wall of the colon, rectum and anal canal, and can determine whether there is any lesion in each part of the colon, rectum and anal canal, and it can be used to take tissue biopsy samples with the auxiliary instruments according to the examination situation, or to carry out the corresponding treatment. 2. Electronic small bowel examination: mainly used for small bowel examination, most commonly used in inflammatory bowel disease (e.g. Crohn’s disease), can directly observe whether there are abnormalities in the small bowel. If a lesion is present in the small intestine, microscopic treatments such as hemostasis, obtaining biopsy samples, polypectomy, mucosal resection, stricture dilation, and lesion labeling can also be performed. If the patient needs to undergo colonoscopy, it is recommended to visit a specialized hospital, cooperate with the doctor for physical assessment and anesthesia risk assessment, and choose the appropriate way to perform the examination according to the condition.