Initially, constipation causes anal tears, i.e. fresh anal fissures, which can heal with medication or constipation relief; however, constipation later causes the fissures to reopen, and so on repeatedly, i.e. old anal fissures. Typical symptoms are constipation, pain, and blood in the stool. The pain is relieved briefly after the feces is expelled, but after a few minutes, the sphincter muscle spasms reflexively, causing intense pain for a longer period of time, which can be relieved by painkillers in some cases. Therefore, patients with anal fissures are afraid of defecation, making constipation even worse and forming a vicious circle. A small amount of bleeding may occur from the fissure, dripping blood on the surface of the stool or after defecation.