There is increasing evidence about the involvement of eosinophils in the pathogenesis of inflammatory bowel disease. We report here two patients with ulcerative colitis who were initially diagnosed as eosinophilic colitis based on histopathological examination during their first attacks. They had symptomatic improvement with ketotifen and metronidazole during their first attacks. However, subsequent attacks which were histopathologically diagnosed as ulcerative colitis did not resolve with the above-mentioned treatment and necessitated a treatment with 5-ASA agents plus corticosteroids. Azathioprine also had to be added in the treatment of the second patient. Dense eosinophilic infiltration in these cases may suggest a role of eosinophils in the initiation of attacks in some ulcerative colitis patients.