There are many special diets that have been developed for the colonic preparation for barium-enema study. To select the better diet for colonic radiological study, prospective randomized study was performed. Sixty consecutive patients visited for colonic examinations were randomly assigned to Boncolon® diet group and Enimaclin® diet group. The patients were questionaired for taste of the given diet and their satisfaction with it. Colonic preparation for barium-enema radiological study was compared in Boncolon® and Enimaclin® diets. The patients accepted Enimaclin® diet as a more favorable and satisfactory diet. Although amount of food contained in Enimaclin® was larger than that in Boncolon® diet, colonic preparation status was similar in Enimaclinadministered and in Boncolon-administered cases when the diet was prescribed to patients without chronic constipation. In summary, Enimaclin® was similar to Boncolon® diet in respect of colonic preparation while showed a better acceptability by patients in terms of the taste.