The chronic course of idiopathic intestinal inflammations is characterized also by a relatively high incidence of complications, local ones affecting the entire large intestine, as well as extrain- testinal ones in remote organs. In the submitted paper the authors present the results of a six- year follow-up focused on the incidence of dysplastic changes of the intestinal mucosa and colorectal carcinoma in 46 patients from a group of 220 patients followed up on a long-term basis at the Second Medical Clinic of the Faculty Hospital and Medical Faculty Olomouc because of the extensive type of ulcerative colitis. The incidence of these complications is not high in our group and is only slightly higher than in the general population. As it is however a very serious disease and so far an optimal algorithm for its follow up has not been elaborated, we feel it is useful to investigate this high risk group of patients after 6-24-month intervals according to the confirmed grade of dysplasia of the intestinal mucosa.

        Key words: Ulcerative colitis - Dysplasia - Colorectal carcinoma