Anal abscesses and anal fistulas are caused by inflammation of the anal glands in the area of the sphincter muscle. The painful abscess is the acute variant of the inflammation with suppuration. It has to opened by way of surgery. The chronic fistula exists in an open connection between the skin around the anus and the interior of the anal orifice and also requires surgery. There are different methods depending on the situation. If the fistula only comprises small parts of the sphincter muscle, a simple fistulotomy may be sufficient. If the fistual extends deeper into the sphincter muscle, it may be excised completely and closed on the colon side by sewing (mucosal flap). Alternatively, removing the fistula after splitting the sphincter muscle and subsequently sewing the sphincter muscle may be possible (sphincter reconstruction). Recently a procedure more gentle on the sphincter has become available. As part of this, the fistula is plugged with a peg of biological material (plug).