Blood in the stool is always caused by rectal polyps, intestinal tumors, hemorrhoids, anal fissures and other diseases, as follows: 1. This disease not only affects the function of the intestinal tract, but also causes local tissue erosion and corruption when it enters the middle and late stages, thus causing the phenomenon of bleeding; 3. Patients with hemorrhoids have constipation, because the feces will cause compression of the venous mass, thus causing the venous mass to rupture and bleeding, but the patient’s blood is fresh, and some people will have jet bleeding; 4. The bleeding will be accompanied by severe anal pain that lasts for a long time, and some people will also form old anal fissures.