Anal fissures are small ulcers formed after the skin layer of the anal canal below the dentate line is cracked. It is parallel to the longitudinal axis of the anal canal, 0.5 to 1.0 cm long, poke-shaped or oval, and often causes severe perianal pain. The majority of fissures are located in the posterior midline of the anal canal or in the anterior midline, and rarely occur laterally. If a lateral fissure is present, the possibility of inflammatory bowel disease or tumor should be considered. Patients with anal fissures have the typical clinical manifestations of pain, constipation and bleeding. The pain is mostly severe and has a typical periodicity. During defecation, due to the stimulation of the nerve endings in the anus, the patient will immediately feel a burning or cutting pain in the anus, which is called pain during defecation. The pain is relieved after the sphincter is fatigued and relaxed, but the pain occurs again when defecating again. The above is called the anal fissure pain cycle. Patients are reluctant to defecate for fear of pain, which in time leads to constipation and drier stools, which in turn aggravates the fissure, forming a vicious cycle. A small amount of blood or drops of fresh blood is often seen on the surface of the stool or on the stool paper during defecation, and heavy bleeding is rare. It should be noted that acute or incipient anal fissures can be cured by effective treatment, such as herbal sitz baths and stool softening methods and local medication, but if the fissure is longer (more than 3 months), the symptoms are heavy (severe pain in the anus after stool lasts for several hours or even longer), or conservative treatment is ineffective, you need to decisively choose surgery to relieve the pain.