The appearance of small meatus in the anus can be divided into the following causes: first, the more common hemorrhoids, thrombosed external hemorrhoids will present in the initial stage, accompanied by local pain and bleeding. Second, local polyps and other benign lesions, such as local moles, hemangiomas, lipomas, sebaceous cysts, etc., which are mainly different reactions caused by local skin friction, and are very simple to treat, with local excision or laser treatment, and are not easily recurring. The third consideration is sexually transmitted diseases, such as condyloma acuminata, which is caused by local viral infection after impure sexual intercourse, mainly in the anal area skin and mucous membrane junction, need to go to the hospital dermatology or urology diagnosis, must be local laser treatment as well as systemic treatment.