Perianal abscesses can be divided into two main categories depending on whether they are associated with the anal fossa: the first category is called fistulous abscesses when the infection is caused by the anal fossa; the second category is called non-fistulous abscesses when the infection is not related to the anal fossa. The majority of perianal abscesses belong to the first category, i.e. the root of the disease is in the rectal sinus, where the infection first starts and then spreads to the loose tissue of the perianal rectal space, and the wound formed by breaking or cutting on the anal skin is only the secondary external opening of the abscess, while the real place where the abscess is caused is the primary internal opening in the rectum. Thus an abscess has two or more openings, one external and one internal. From the external opening, sometimes it can be temporarily closed due to pus drainage and reduction of inflammation, and the patient feels as if it is healed. But in essence, because the infectious secretion in the inner opening cannot flow out, of course, it cannot heal, when feces or other dirty things enter, it will cause or aggravate the infection again, swelling and pus, flowing out along the original wound, and some break out from the new place, so repeatedly, often pus, itching, underwear is always unclean, so that patients feel very annoyed, after strenuous activities due to pus stimulation, skin friction The pain is aggravated by pus irritation and skin friction after strenuous activities, which affects work and labor. In contrast, non-fistula abscesses, which account for a small percentage of perianal abscesses, can be cured by general incision and drainage without forming an anal fistula. As a result, the vast majority of perianal abscesses turn into anal fistulas, but there are no accurate statistics on the exact percentage.