Normal menstrual blood does not come out of the anus. Menstruation is caused by the shedding of the uterine lining, which will flow out through the cervix and be discharged from the vagina. There is a muscular interval between the vagina and the anus, so women’s anal bleeding during menstruation may be related to anorectal fistula, hemorrhoids, gastrointestinal bleeding and other diseases.1, rectovaginal fistula: it can occur after surgical operation or childbirth, the patient can see the vaginal defecation and discharge, and the menstrual blood discharged from the anus. Clinically commonly used surgical treatment of this condition; 2, hemorrhoids: women use sanitary napkins or frequent use of paper products during menstruation, may stimulate hemorrhoids, making the symptoms worse. At this time, the anal outflow is not menstrual blood, but hemorrhoidal bleeding. You can use Ma Yinglong musk hemorrhoid suppository for treatment, and change sanitary napkins diligently during menstruation; 3, gastrointestinal bleeding: if gastrointestinal bleeding occurs during menstruation, it may be mistaken for menstrual blood flowing out of the anus, and patients with gastrointestinal bleeding may experience epigastric pain and blood in the stool. Further clinical examination is needed to clarify the site and source of bleeding for targeted treatment. Overall, menstrual blood does not come out of the anus directly, and there are many issues to consider if there is anal bleeding during menstruation. You can go to gynecology, general surgery or gastroenterology based on the diseases listed above and your symptoms. During menstruation, it is important to protect yourself from cold and warmth, get plenty of rest, and supplement your diet. If hemorrhoids are the cause, regulate your diet and eat more foods rich in dietary fiber.