Serial double-contrast barium enema examinations were performed in 40 patients with nongangrenous ischemic colitis, 15 with the stricturing form and 25 with the transient form. Thumb-printing was observed in 30 cases (75%); it appeared within 9 days after the onset of the disease in patients with the stricturing form and within 6 days in those with the transient form. Thumb-printing disappeared about 10 days after the onset, but it lasted considerably longer in two patients with the stricturing form (21 and 29 days, respectively). Longitudinal ulcers were observed in 24 patients (60%), and healing was confirmed on day 20 or later in patients with the stricturing form and on day 9 or later in those with the transient form. Eccentric deformity was found in 19 patients (48%), sacculation in 12 (30%), and transverse ridging in five (13%). These results indicate that longitudinal ulcers and thumb-printing are both characteristic findings of ischemic colitis. The double-contrast study is useful for visualization of the ulcer.