The crack behind the anus is generally referred to as anal fissure, because of individual differences, there is no anal fissure with what medicine is good. The etiology of anal fissure is not completely clear, but it is closely related to the mechanical trauma caused by dry stools and so on. Anal fissure patients can follow the doctor’s instructions to use painkillers, laxatives and other drugs to relieve symptoms. Anal fissure patients in defecation, usually feel anal burning or cutting pain, but after a few minutes can be relieved, some patients are afraid of defecation, resulting in the formation of a vicious circle. At this time, patients can follow the doctor’s instructions to use local analgesic drugs, such as lidocaine gel, to reduce pain. If constipation is severe, oral laxatives, such as lactulose, polyethylene glycol electrolytes, etc., can be used to help improve the symptoms. If conservative treatment is ineffective, surgery such as anal fissure resection and internal anal sphincterotomy can be chosen after evaluation by a doctor. However, there are also a small number of mild cases that can be treated by using potassium permanganate sitz baths and dietary modifications, etc. It is recommended that patients go to the hospital in a timely manner for standardized treatment under the guidance of a doctor.