A retrospective trial was carried out comparing four methods of bowel preparation on a randomly selected group of 503 patients. The methods of bowel preparations were: (1) X-prep alone, (2) X-prep plus three-day diet, (3) X-prep plus high colonic washout, (4) X-prep plus high colonic washout and three day diet. Faecal content was assessed independently by three radiologists and recorded on a linear analogue scale. Statistically significant differences were shown between the results obtained by each method; 97% of patients prepared by method (4) were acceptable, 89% of method (2), 83% of method (3) and 71% of method (1). It was also found that in-patients exposed to the same method of preparation as out-patients showed inferior bowel cleanliness although not to a statistically significant degree.