This is a summary of 96 Falk's Symposium, which took place in Freiburg (Germany) from 30.10 to 1.11.1996. In the article you can find the latest information about etiology and treatment of inflammatory bowel diseases. The following factors in etiopatogenesis of the diseases are described: genetical, bacterial, immunological, cigarette smoking and the influence of nitric oxide. The use of aminosalicylates, corticosteroids, immunomodulators and antibiotics in conservative treatment is presented. There is also a short notice about surgery.