An anal fistula, a tube between an intra-anal infected lesion and the perianal skin, consists of three parts: an internal opening, a fistula, and an external opening. The internal opening is often located in the anal canal, mostly one; the external opening is on the perianal skin, which can be one or more, and is recurrent over time or intermittently, and is one of the common rectal and anal canal diseases. The prevalence rate is high, second only to hemorrhoids, accounting for 1.67-3.6% of the incidence of anorectal diseases in China, the peak age of incidence is 20-40 years old, infants and children also have more incidences, more men than women, the male to female ratio of 5-6:1. The high incidence rate of men is related to the male sebaceous gland secretion, after 20 years old to 50 years old, the highest incidence rate of men, in adolescence, the body’s own sex hormones become active, according to The study of male testosterone is directly related to anal fistula. The first thing you need to do is to get a good idea of what you are getting into. The male patient has a stressful life, a taste for spicy food, a lot of alcohol, and secretion of acid, which stimulates the anal sinus and can easily lead to infection. The common cause of anal fistula is the narrowing of the pus cavity after the perianal abscess breaks down on its own or after surgical incision and drainage, which becomes tubular and the rupture shrinks and cannot heal itself. The main symptoms are as follows: (1) discharge of pus, secretions or blood from the external mouth, more pus from the newly created fistula, pus is sticky, yellow and smelly; less pus from the long-standing fistula, sometimes intermittent, pus is thin and light; sometimes the fistula mouth is temporarily closed, local swelling and pain can occur, which can be relieved after breaking. (2) pain: fistulas are often painless without inflammation, and only hard strips or lumps can be palpated on the outside of the anus. If the fistula is temporarily closed, or if the internal opening is large and stool flows into the fistula, pain can occur, which is aggravated by defecation. (3) Systemic symptoms: Simple anal fistulas often have no systemic symptoms, while complex anal fistulas and fistulas with large lesions that are repeatedly inflamed and abscessed often have symptoms such as low-grade fever, weakness, and anemia. Anal fistulas do not heal on their own. Untreated recurrent perirectal abscesses can occur and therefore must be treated surgically. The principle of treatment is to incise or excise the fistula to create an open wound and induce healing. There are many surgical options, and surgery should be selected based on the height of the internal opening and the relationship between the fistula and the anal sphincter. The key to surgery is to minimize damage to the anal sphincter to prevent anal incontinence and to avoid recurrence of anal fistula. The main surgical methods are as follows: 1. Fistulotomy, a method in which the fistula is completely cut open and the wound is healed by the growth of granulation tissue. It is suitable for low anal fistula. The method is a slow incision of the fistula using the mechanical compression of a rubber band or corrosive thread. The method also has the advantages of simple operation, less bleeding, convenient drug changes, and no skin incision adhesions before the rubber band falls off. It is mostly used for high anal fistula. 3.Anal fistula excision, cut the fistula and remove all the fistula wall to healthy tissue, the wound is not sutured; if the wound is large, it can be partially sutured, partially open and filled with oil gauze, so that the wound grows from bottom to outside until it heals. It is suitable for low anal fistula.