Authors present case of a 28-year old woman with skin symptoms of pyoderma gangrenosum and ulcerative colitis seriously advanced. The patient benefited from wide resection of the colon and steroid therapy. The other patient was 23-year old woman with ulcerative colitis concomitant with skin changes of erythema nodosum. In this case steroid therapy gave also a very good effect. We tried to find pathogenetic connection between these diseases based on the reports from the medical literature.