Basis treatment of severe ulcerative colitis and Crohn's disease comprises the systemic administration of corticosteroids. If the conditions are less severe, treatment with oral sulfasalazine or 5-aminosalicylic acid (5-ASA) can be attempted. Distal ulcerative colitis may respond to topical corticosteroids of enemas with sulfasalazine or 5-ASA. In long-term treatment with high-dose corticosteroids, azathioprine and 6-mercaptopurine may be employed to reduce the corticosteroid requirement. There ist no known generally applicable diet for the treatment or prophylaxis of these conditions.