There are many reasons for a little blood when wiping the buttocks, as follows: the first, more common is anal fissure, if dry stool or foreign body damage, resulting in anal canal skin fissures, in wiping the stool manifested as the surface of the stool with blood, blood in the stool is usually bright red, perianal visual examination can clearly see a fissure, the trauma edge is sometimes relatively neat. The second, blood when wiping the buttocks may also be hemorrhoids, especially internal hemorrhoids, which are located above the dentate line and are a mass of varicose veins. With increased abdominal pressure or constipation, a diet with a lot of irritating foods, such as chili peppers or a lot of alcohol, can lead to swelling of the hemorrhoid nucleus and rupture of the hemorrhoid vein resulting in bleeding. Blood in the stool is usually bright red, dripping or spraying, and can be clearly diagnosed by rectal examination or anoscopy. Thirdly, blood when wiping the buttocks may also be rectal polyps, rectal adenomas or rectal malignant tumors, which can erode the blood vessels under the mucosa of the rectum and cause bleeding, and can be diagnosed by rectal diagnosis or anoscopy.