Blood on the buttocks consider trauma, anorectal disease, women should also consider menstrual or menstrual disease, uterine disease and so on. 1. Trauma: If the skin on the buttocks inadvertently scratched or stabbed, may lead to bleeding, such as shallow wounds, no infection can be iodine povidone simple disinfection; but the wound is deeper with a tendency to pus, you need to consult a doctor for anti-infective treatment, and if necessary, inoculation of tetanus vaccine. 2. Anal and intestinal diseases: hemorrhoids, anal fissure, anal fistula, perianal abscess, as well as anal and intestinal tumor ulceration. A few can be because of walking, exercise and other reasons, friction to the affected area and bleeding; most of them are bleeding during defecation, and most of them are accompanied by anal pain, tearing pain, constipation and other symptoms. You need to go to anorectal department for targeted treatment. 3. Women’s special period or disease: women’s menstruation will be due to endothelial shedding and bleeding, some women just bleeding without other discomfort, so it is not easy to find. In addition, if there is a menstrual disease, such as irregular menstruation, bleeding between periods, etc. will also be in the buttocks, underwear stained with blood. Certain inflammatory conditions of the uterus can result in a dark brown abnormal vaginal discharge that may be thought to be blood. Older women with vaginal bleeding after menopause should especially consider gynecologic tumors. Such cases should be examined by a gynecologist and treated by a specialist. There are many reasons for blood on the buttocks, and if you cannot identify the cause, you should seek medical attention.