As the public’s alertness to colorectal cancer increases, more and more people are seeking timely medical treatment for blood in stool. However, there is a kind of improper practice which is very common in our country, that is, no matter the patient or the doctor encounters the person with fresh blood in the stool, he or she will go through colonoscopy first, and as a result, a large part of the patients’ bleeding foci can not be found at all. In fact, the vast majority of blood in the stool bleeding foci in the anorectal, and many are wounds can be quickly repaired anal fissure, hemorrhoids and so on. If the first colonoscopy, must first make an appointment to check the time and do intestinal preparation, wait until the examination when the wound has long been healed, and the long colonoscopy is not very suitable for the observation of anal foci. The correct approach is that, once the blood in the stool, should be the same day or the next day to the hospital (preferably anorectal) to let the doctor to do anorectal examination, the doctor through the naked eye and anoscopy observation most of the causes of the bleeding can be clear, and did not find the lesions and then consider further colorectal examination. It must be pointed out that the discovery of bleeding lesions in the anorectum does not mean that there is no lesion in the upper section of the colon, nor does it mean that colonoscopy is not necessary at all, and the doctor will decide according to the specific condition. In view of the sharp rise in the incidence of colorectal cancer in recent years, even after the discovery of anorectal bleeding foci, for the age of 40-50 years of age, it is best to carry out a physical examination of the nature of the colonoscopy, to find and remove intestinal polyps, to prevent the problem before it occurs.