There are several reasons for anal pain during menstruation: 1, the uterus is in the state of posterior flexion and posterior tilt, the pelvis is congested during menstruation, coupled with menstrual blood in the uterine cavity, which will stimulate the rectum, causing localized pain in the rectum. It is best to take the prone position and lie on the bed to rest during menstruation. It is recommended to apply a hot water bag to the waist to promote local blood circulation, so that menstrual blood flows more smoothly, reducing the feeling of anal pain during menstruation.2, endometriosis foci in the rectum, menstruation when the endometrium is shed, the foci of the endometriosis will also appear to bleed, it will cause anal pain. The pain is relatively serious and often seriously interferes with the patient’s daily life and work, and further examination and treatment are recommended.