Zdenek Mařatka has been the first physician, who had brought a new information for the Czech medical community with topic of inflammatory bowel diseases, which had been systematic studied for him. He had prepared an original theory - two component hypothesis about origin of ulcerative colitis, which had been developed and innovated by him for long time. From the international point of view, Mařatka has had an extraordinary impact and significant contribution for recognition of ulcerative colitis and Crohn´s disease. Despite the fact that the true origin of ulcerative colitis and Crohn´s disease (UC) still remain elusive, basic as well as clinical research bring many new data on etiology and pathogenesis of this inflammatory condition. It seems clear that IBD originate from interaction of several intrinsic and extrinsic factors that contribute individually in a particular patient. Among internal factors the genes play an important role, because its influence on the mucosal immunity system and immunological response. Among the external factors importance are recognized the gut microbiota content, cigarette smoking and psychological stress.