There are many reasons for blood in the stool: first, it may be bleeding hemorrhoids, hemorrhoids are varicose veins, usually when constipation or increased abdominal pressure, resulting in swelling of hemorrhoidal veins, hemorrhoidal vein rupture and bleeding, especially the main symptom of internal hemorrhoids is painless blood dripping or spraying; second, blood in the stool may be anal fissures, such as dry stool easily damage the skin of the anal canal, and lead to trauma at the anal opening, stool Third, if there are rectal polyps or rectal adenomas, stimulation of the rectal mucosa on the surface of the polyps during stool can lead to local bleeding; fourth, if there is a malignant rectal tumor, it can also invade the mucosa or the blood vessels under the mucosa and lead to bleeding. Therefore, there are many causes of fecal bleeding, we should combine medical history, physical examination and, if necessary, anoscopy or colonoscopy to clarify the cause of bleeding.