Objective: To determine the optimal volume of abdominal irrigation that will prevent surgical site infections (both deep and superficial), eviscerations and fistula formations; and improve 30-day mortality in trauma patients.Methods: We conducted a three-arm parallel clinical superiority randomized controlled trial comparing different volumes of effluent (5, 10 and 20 liters) used in trauma patients (both blunt and penetrating) age 14 and above undergoing an emergency laparotomy between April 2002 and July 2004 in a busy urban Level 1 trauma center.Results: After randomization, a total of 204 patients were analyzed. All patient groups were comparable with respect to age, gender distribution, admission injury severity score, and mechanism of injury, estimated blood loss and degree of contamination. The mortality rate overall was 1.96% (4/204).No differences were noted with respect to contamination, wound infection, fistula formation, and evisceration. The twenty liter group (Group III) showed a trend toward an increased incidence of deep surgical site infections when compared to the five liter (Group I) (p=0.051) and ten liter (Group II) (p=0.057) groups. This did not however reach statistical significance.Conclusion: The old surgical adage “the solution to pollution is dilution” is not applicable to trauma patients. Our results suggest that using more irrigation, even when large amounts of contamination have occurred, does not reduce post-operative complications or affect mortality; and it may predispose patients to increased incidence of abscess formation.(Trial registration number: ISRCTN66454589).