Stomas may be divided into three classifications, i.e. input stomas, diverting stomas, and output stomas. Input stomas are usually temporary and facilitate nutrients being put into the gut. Diverting stomas divert the contents of the gastrointestinal tract away from diseased or damaged gut. Output stomas provide an outlet for the elimination of body waste, usually following excision of an excretory organ. There are a variety of conditions, which may predispose to surgery involving the creation of a stoma. The most common conditions are described in the chapter.