Ulcerative colitis: false-colour double-contrast barium enema X-ray of the large intestine (coloured red) in ulcerative colitis. Colitis is a general term for inflammation of the colon, symptoms of which include diarrhoea & abdominal pain; the rectum may also be involved. Its cause is obscure; food allergies & infective agents have been considered. Barium enemas are taken to show the extent & severity of the disease. Mild cases display an abnormal mucosal pattern (as at left, in the ascending colon); more severe disease shows multiple ulceration. The disease commonly follows a chronic course, characterised by periods of remission and relapse.