The scope of observation of colonoscopy is large, and the scope of observation of anoscopy is small, there is no need to do anoscopy after colonoscopy. Anoscopy is mainly through the anus into the observation of the anus, part of the rectum and other internal mucosa and its lesions. And enteroscopy is also from the anus into, but enteroscopy observation range is wider, can also observe the anus, rectum and colon, enteroscopy can be observed to the parts of the anoscope can not be observed, so enteroscopy is done, the patient does not need to do anoscopy. When patients have intestinal dysfunction, abdominal pain, blood in the stool, dyspepsia and other discomforts, or have high-risk factors, patients with intestinal polyps, familial colon cancer, must regularly review colonoscopy, to avoid delays in treatment due to failure to detect lesions in time.