Crohn's disease. Artwork of a section through part of the human digestive tract, showing the small intestine affected by Crohn's disease, or regional enteritis. The small intestine (at lower right), meets the large intestine (colon, at left) at centre. Between them lies the appendix (at lower centre). Crohn's disease often occurs in the last section of the small intestine, the terminal ileum. The disease produces inflammation (red) and abscesses (white) on the wall of the small intestine. Symptoms include diarrhoea, abdominal pain, loss of appetite and anaemia. The causes are unknown. Treatment includes corticosteroid drugs and sometimes surgery.