The essence of intestinal obstruction is that there is a blockage in the intestine. Impairment of the passage of material through the bowel results in cessation of passage of flatus and faeces. Blockage results in distension of the proximal intestine with solids, fluid and gas; this results in pain, an increase in abdominal girth, and increased tension in the intestinal wall. Increased tension in the intestinal wall and/or impairment of the blood supply of the intestine due to twisting and external pressure results in necrosis and perforation of the bowel. Blockage of the intestine with distension and/or impairment to its blood supply will result in activation of local and systemic inflammatory responses and translocation of bacteria through the wall of the intestine.