The gastrointestinal symptoms of Behçet's disease are ancillary manifestations of this disorder reflected principally in the form of diarrhea, abdominal pain, meteorism, nausea, and loss of appetite. If radiological changes can be detected they generally appear as dilatation of the small intestine or ulceration at different levels of the digestive tract. In our patient the intestinal symptoms started with dilation of the ileum and then toxic megacolon developed. At later follow-up examinations the radiological picture resembled Crohn's disease and ischemic colitis of the entire organ. It has been repeatedly, and wrongly, stated that there is an association between Behçet's disease and Crohn's disease or ulcerative colitis. Rather, it should be assumed that the intestinal manifestations of Behçet's disease correspond to those of Crohn's disease and ulcerative colitis without these diseases being actually present. The evolution towards toxic megacolon may be the consequence of a transmural infection across the colonic wall deriving from the mucosal ulcerations of colon and sigmoid, and proves that toxic megacolon is not a pecific complication of ulcerative colitis but may appear in the course of any acute inflammatory ulcerative lesion of the colonic wall.