The therapy of inflammatory bowel diseases (Crohn's disease, ulcerative colitis) has been improved in recent years. This is mainly due to our better understanding of application of aminosalicylates and steroids in regard to localization, activity, and type of chronic inflammatory bowel disease. Newly developed aminosalicylates like mesalazine provoke less side effects. Furthermore, they seem to be effective in the treatment of ileal inflammation of Crohn's disease. Therapy with immunosuppressive drugs like mercaptopurine, azathioprine, and cyclosporin A is justified in case of steroid-resistant Crohn's disease. Alternative therapeutic concepts are at present at the stage of clinical trial.