OBJECTIVE: To assess the effect of preoperative enemas on the recovery of peristalsis after non-colonic abdominal operations. DESIGN: Prospective randomised trail. SETTING: University hospital, Switzerland. SUBJECTS: 116 adult patients (> 16 year old) about to undergo elective non-colonic abdominal operations under general anaesthaesia were considered. INTERVENTION: Two groups were randomised to receive a one litre water and glycerine enema the day before operation (n = 53) or no preoperative intestinal preparation (n = 53). MAIN OUTCOME MEASURES: Return of peristalsis after operation, assessed by auscultation of bowel sounds and time of the first spontaneous faeces. All participants were followed daily for 10 days or until discharge by the same observer. RESULTS: 110 patients gave informed consent, 6 refused to participate, and 4 had to be withdrawn after randomisation, leaving 106 for analysis. The patients without an enema recovered bowel sounds activity sooner (p = 0.02) and passed their first spontaneous faeces significantly earlier (p = 0.01). No subgroup of patients benefited from an enema. CONCLUSION: Preoperative enemas delay rather than improve the return of normal peristalsis after surgery. We recommend this practice should be abandoned.