Fistula is a common disease in anorectology, called anal fistula in Chinese medicine, and is second only to hemorrhoids in anorectology. A fistula is formed by the breakdown of a perianal abscess, which is an inflammation of the anal sinus that causes a red swelling around the anus. After the use of antibiotics or the control of inflammation, it can break down, and after it breaks down, an external opening is formed and a fistula is formed, and an anal fistula is formed. An anal fistula consists of three parts, formed by an internal opening, an external opening, and a fistula. The clinical symptom of anal fistula is repeated external opening rupture and pus flow, usually without pain or fever. This disease is not treated effectively with medication and can only be treated with surgery.