Anal fissure blood in stool is anal fissure accompanied by pain and bleeding, the color of bleeding is bright red, there will be dripping blood after the stool, and the pain is particularly obvious, there will be relief after the stool and then the pain of this pattern. Bleeding caused by bowel cancer in the early stage is a painless bloody stool, blood is dark red, blood clots or accompanied by mucus. In the late stage of disease progression, it will be accompanied by pain in the anus or a feeling of urgency and heaviness, and the bleeding is also accompanied by dark red blood and mucus, with a certain fishy odor. The most fundamental difference between these two diseases can be performed electronic colonoscopy, for bowel cancer and anal fissure colonoscopy at a glance, and at the same time for intestinal cancer can be taken pathology, through the pathology of the diagnosis is more accurate.