The aim of this study was to compare the efficacy of three forms of cleansing enema for rigid proctosigmoidoscopy. One hundred fifty five patients referred for proctosigmoidoscopy to the Department of Surgery at the FEU-NRMF Medical Center were randomly assigned by simple random sampling into three groups to receive three forms of cleansing enema: monobasic sodium phosphate dibasic sodium phosphate (Fleet Enema ) for Group 1 (n=42), sorbitol and dioctyl sulfosuccinate ( Clyss Go) for Group 2 (n=38) and soap sud enema (SS Enema) for Group 3 (n=45). Quality of bowel preparation was graded as good, fair or poor. The cleansing enema was administered one hour prior to the procedure. It was readministered in case the patient did not have bowel movements. Another dose of the designated enema was given if the bowel preparation was poor. The reinfusion rate for the SS enema group was only 17 percent, significantly lower than the 45 percent of the Fleet Enema group (p=0.01), but not statistically different from the 39 percent of the Clyss Go group (p=0.05). The cost-effective analysis using direct costs showed SS enema was more cost- effective than Fleet Enema or Clyss Go enema. The SS enema was a good alternative for cleansing the bowel prior to rigid proctosigmoidoscopy. It had a low reinfusion rate and was more cost-effective than Fleet enema or Clyss Go. (Author)