Twenty-five cases of non-infectious, macroscopic colitis, observed consecutively in patients over 70, were studied. The final diagnosis was, in 12 instances, ischemic colitis, in 10 instances cryptogenetic colitis (6 ulcerative colitis and 4 Crohn's diseases), and in 3 instances, non-classified colitis. The clinical manifestations consisted of rectal bleeding (92%), abdominal pain (76%) and diarrhea (56%). In 3 cases, the ano-perineal lesions observed in Crohn's diseases were noted and, in one case, a pyoderma gangrenosum was present. Endoscopy and/or barium enema showed a lesion of the left colon in 92% of the cases and of the sigmoid colon in 80% of the cases. The prognosis was severe, requiring surgery in 32% of the cases (5 ischemic colitis, 3 cryptogenetic colitis), and a 24% mortality (3 ischemic colitis, 3 ulcerative colitis), secondary to the condition and the extent of the colic involvement. The best factors of the etiological diagnosis of colitis were: the type of onset of the symptoms, the presence of anal or cutaneous lesions, the information provided by endoscopy and histology, which were specific in 11 out of 20 cases. In 5 cases, the diagnosis was only made by examination of the surgical specimen; in 3 cases, the diagnosis remained uncertain. These results suggest that the clinical data combined with an early, minimally traumatizing left endoscopy in elderly patients, should allow a quick, positive and etiological diagnosis of colitis, in order to initiate a suitable treatment in most cases.