[Etiology of chronic inflammatory bowel diseases].

Furthermore the aetiopathogenesis of inflammatory bowel disease (IBD) is unknown. The familial accumulation makes a genetic disposition probable. Presumably, the development of Crohn's disease and ulcerative colitis is contingent upon several factors, including perhaps environmental factors in the broadest sense. A large number of microorganisms have been implicated, but there is still no convincing proof that any of them have an important role in the aetiopathogenesis of IBD. The observed immunological phenomena are as yet difficult to interpret.