Why is bleeding in the stool?

Fecal bleeding is mainly caused by the following diseases: 1, hemorrhoids, mainly internal hemorrhoids, internal hemorrhoids patients often show blood when the stool, dripping blood. Patients often because of prolonged sedentary, activity decline or long-term constipation caused by adhesion to the rectal wall anal pad congestion down, the formation of hemorrhoids, dry stool friction prolapse hemorrhoids during defecation, resulting in hemorrhoids rupture bleeding. A small number of patients caused by external hemorrhoids, patients with rectal venous plexus congestion expansion, easy to show stool bleeding. 2. Some patients are caused by anal fissure. When patients defecate due to constipation and dry stool for a long time, the mechanical system damages the rectal wall or anal canal, causing anal bleeding. 3. Due to gastrointestinal bleeding, such as gastric and duodenal ulcers or massive bleeding. 4. Some elderly patients may be caused by intestinal cancer or polyps.