Crohn's disease, pill camera view. The lining of the ileum, the last part of the small intestine, is severely inflamed here. Crohn's disease is an inflammatory disease of the digestive system. It usually affects the ileum and the colon (the largest part of the large intestine), but the ulcers and inflammation can occur anywhere in the digestive tract. Its cause is not fully understood, but it is thought to be related to either a weakened immune system or an autoimmune reaction (where the immune system attacks the body's own tissues). There is no cure, but steroids and careful control of the diet can help. In severe cases, parts of the digestive tract may be surgically removed. A pill camera is a pill- sized camera swallowed to image the digestive tract.