An anal fistula is an abnormal passage that occurs between the lower end of the anal canal or rectum and the skin adjacent to the anus. It is a sequel to an infection in and around the lower end of the anal canal and rectum. It is mostly seen in adults and is common among anal diseases. There are several reasons for the recurrence of the disease after anal fistula surgery: Cause 1 Improper treatment of anal glands: According to recent studies, anal gland infection is an important cause of anal fistula, therefore, it is important to remove the clean inner opening, as well as the anal glands and anal gland ducts with inflammation near the inner opening. Cause 2: Incomplete removal of fistula branches and their fistula cavities: i.e. not scraping the necrotic tissue or removing the branches during surgery, which can lead to recurrence. Cause 3: Improper treatment of the internal orifice: Most of them are due to inaccurate search of the internal orifice or incomplete removal of the primary focus of infection, i.e., the internal orifice. Cause 4 newly generated anal fistula: Most patients have a new anal fistula due to an anal gland infection and a perianal abscess, which is mistaken for a recurrence and is not difficult to identify in the clinic. Cause V complex internal orifice: i.e., when there are two or more fistula internal orifices, the search for the internal orifice is incomplete, leading to recurrence.