Crohn's disease. Endoscopic view of the interior of a patient's neoterminal ileum affected by Crohn's disease, showing ulceration (white). Crohn's disease causes inflammation, thickening, and ulceration of the intestinal tract. It often occurs in the ileum of the small intestine and in the colon (large intestine). Its cause is unknown and there is no cure. Symptoms include abdominal pain, diarrhoea and the malabsorption of food, leading to weight loss. Treatment normally involves controlling the symptoms and maintaining remission where possible, using anti-inflammatory drugs and immunosuppressants. Surgical removal of inflamed regions of the intestine is sometimes also required.