Diagnose of the idiopathic inflammatory bowel disease depends on the set of clinical, radiological, endoscopic and histological criteria. Proctitis, proctosigmoiditis, and the left-sided colitis represent 60 to 80 percent of newly diagnosed cases of colitis. For the medical management of the inflammatory bowel diseases aminosalicylates, corticosteroids, topical corticosteroids, immunosuppressants are used. The complication of highest risk represents the toxic magacolon or periannal fistulas in patients with Crohn´s disease. Pre-neoplastic epithelial changes (dysplasia) are diagnosed by pathologists according sets of cytological and architectonic markers. Indeterminate diarrhea related to the antibiotics administration is comparatively common. Roman criteria II classify functional intestinal disorders, represented by a set of isolated symptoms or various combinations of symptoms without identifiable organic, biochemical, sonographic or endoscopic abnormalities of the intestinal or biliary system, lasting minimally 12 weeks (not necessarily continuously) during the preceding year, as a persisting or recurrent distress. About 20 percent of patients with diverticular disease of the colon have some clinical manifestations.

        Key words: Colon, inflammatory bowel diseases, Crohn´s disease, dysplasias, diarrhea, constipation, diverticulosis.