The causes of blood in the stool are: 1. Anal fissures, fissures with blood in the stool and bright red color, the patient has dry stool, perianal pain and other performance. 2. Hemorrhoids can also appear blood in the stool, usually after the stool dripping blood and the color of blood is bright red, and perianal discomfort performance. 3. May be intestinal tumors, especially the elderly will have wasting, thinning stool and other performance. 4. The patient should undergo colonoscopy in time, and if problems are found, pathological examination should be performed to further clarify the diagnosis. 4. benign polyps of the intestine may also appear blood in the stool. 5. mesenteric vascular occlusion can cause blood in the stool, and the patient will have abdominal pain and other manifestations.