If there is pain in the anus during menstruation, it is often caused by the following clinical reasons: First, the retroflexion and retroversion of the uterus will stimulate the rectum and cause pain in the anus during the bowel movement. Secondly, because of the chronic inflammation of the rectum in the past, when the body resistance decreases during menstruation, the inflammation will be aggravated, so that the anal pain occurs when relieving stool. It is advisable to go to the Department of Proctology to do the appropriate examination to exclude the possibility of rectal inflammation. Thirdly, this condition may also be caused by endometriosis in the rectum, and it is recommended that a detailed examination be performed to differentiate the symptoms. It is recommended to do gynecological examination and anal finger examination after menstruation to find out whether there are local abnormalities.