Painful anal contraction is usually considered to be caused by dry stool, which is often caused by insufficient intake of coarse fiber food, too little water, or lack of exercise and poor bowel habits, resulting in dry stool staying at the anus, which can stimulate the mucous membrane and cause pain when the anus is contracted, and the discomfort can be gradually relieved after the trigger is removed. In addition, the pain can also be considered to be caused by perianal lesions, such as anal fissures, hemorrhoids, perirectal abscesses, anal stenosis, etc., which need to be treated under the guidance of a doctor for the cause: 1. Anal fissures: a common disease that causes pain when the anus is contracted, it is a small ulcer formed after the skin layer of the anal canal under the dentate line is cracked, mostly seen in young and middle-aged people. The direct cause of anal fissures is the mechanical trauma caused by prolonged constipation and dry stool during defecation, and diarrhea is also an important cause of anal fissures. Typical clinical manifestations are pain, constipation and bleeding. The pain is severe and can occur when the anal sphincter contracts and spasms, and usually the patient also experiences perianal burning or cutting pain during defecation. The diagnosis is usually made by the clinician during an anal examination. The onset or early stages of anal fissures can be treated with sitz baths and laxatives, while chronic fissures can be treated with sitz baths, laxatives and anal dilation. For non-surgical treatment is ineffective, and the symptoms are more serious, surgical treatment can be used, such as anal fissure excision, anal canal internal sphincter cut; 2, hemorrhoids: hemorrhoids is the most common anorectal disease, there are internal hemorrhoids, external hemorrhoids, mixed hemorrhoids. When hemorrhoid patients have an increased local hematoma accompanied by perianal infection, they may experience painful symptoms as soon as the anus is contracted. This is usually accompanied by blood in the stool, anal discomfort, and difficulty in defecation. When hemorrhoids become painful, it is recommended to seek medical attention. Non-surgical treatment of hemorrhoids is usually performed, and patients need to increase their intake of high-fiber foods, eat more fruits and vegetables, keep their bowels open, relieve local swelling with sitz baths, and develop good bowel habits. Clinically, injection therapy and rubber ring ligature method have good treatment effects. For patients who cannot undergo non-surgical treatment or treatment failure, surgical treatment can be performed to remove the abscess; 3. perirectal abscess: it is an acute purulent infection of the soft tissue around the rectum and anal canal or its surrounding interstices and forms an abscess, usually due to anal gland infection. Abscesses can cause a feeling of anal swelling and pain when the anus is contracted. Abscess incision and drainage is the main treatment for this disease, while antibiotic treatment, warm water bath, local physiotherapy and diarrhea treatment are given to reduce perianal pain; 4. Anal stenosis: Consider that it may be caused by congenital developmental malformation, or it may be caused by mucosal adhesion due to inflammatory stimulation at the anus, or when the anus is affected by trauma, burns, etc., resulting in scar generation and tumor factors, which can lead to The occurrence of anal stenosis. As the diameter of the anal canal becomes smaller and narrower, and the elasticity of the anal canal becomes worse, painful contraction of the anal canal may occur, which requires surgical treatment, such as anal dilation and radial incision scar release.