Blockade of the ganglion impar was performed as an alternertive means of managing intractable neoplastic perineal pain of sympathetic origin. We successively treated a patient who had suffered from excessive perianal sweating with ganglion impar block using pure alcohol. Eight months after block, the patient has no complaint of perianal sweating. Ganglion impar block is an effective method in the treatment of excessive perianal sweating as well as perineal pain of sympathetic origin.