Crohn's disease. Endoscope view of ulceration in the ileum of a 42 year-old woman, at the site of surgery (anastomosis) to correct Crohn's ileocolitis. Ileocolitis is the form of Crohn's that affects the ileum (the final part of the small intestine). Crohn's disease seems to have both genetic and environmental causes, and is not well understood. Symptoms include abdominal pain, vomiting and diarrhoea. Treatment is with anti-inflammatory drugs or in severe cases (as seen here), the affected area of intestine may be surgically removed.