Small colonoscopy is not only used to examine the small intestine, but also to detect mucosal lesions in the stomach and esophagus when entering through the mouth, and to observe lesions in the colon when entering through the anus. Small enteroscopy is mainly used to examine the small intestine lesions, can be observed in the duodenum descending to the upper one-half of the jejunum and the ileum. Other areas can also be examined during access to the small intestine. If the small colonoscope is accessed through the mouth, mucosal lesions in the stomach and esophagus can also be detected; when accessed through the anus, lesions in the colon can be observed. Small colonoscopy helps to diagnose small bowel-related diseases and chronic gastrointestinal bleeding, and can also be used for polyp removal and hemostatic treatment, and it can also be used to take tissues from the lesions for relevant pathology examinations. As each patient’s condition is different, the method of examination also varies, and the decision of whether or not to perform a small colonoscopy needs to be made by a medical professional.