The colon is mostly between 100-130 cm long and withdraws water from the bowel content to recycle it to the body. Due to the abundant content of bacteria in the colon acute and recurrent infammations are frequent. This is especially true if so called diverticula are present (benign extrusion of the mucosa through the bowel wall). In chronic inflammation there is sometimes overshooting of the immune response to feces contents or colonic mucosal cells (ulcerative colitis). Unfortunately, there is an increasing frequency of colon cancer in western countries. On the other hand the increasing use of preventive screening colonoscopy leads to earlier diagnosis and better prognosis.