Anal fissure is a very common anal disease, which is basically caused by the mechanical trauma of anal canal caused by dry stool and difficult defecation. Anal fissure is divided into acute anal fissure and chronic anal fissure, and chronic anal fissure is often an old anal fissure. Old anal fissure wound fibrosis, often difficult to self heal, this situation requires surgery. During the operation, the old anal fissure wound must be removed until fresh tissue is exposed, changing the old anal fissure into fresh anal fissure. At the same time, part of the internal anal sphincter should be loosened to gain time for the wound healing of fresh anal fissure. After the operation, you must eat more fresh fruits and vegetables to keep your stool smooth, avoid forced defecation and dry stool. After defecation, clean up the residual feces and secretions on the wound in time, so that the anal fissure can be quickly healed.