The aim of this study was to compare the efficacy and patient tolerance of a new pulsed irrigation system to colonic lavage for colonoscopic preparation. Thirty-four prospective patients scheduled for routine colonoscopy were randomized to one of two preparations: a per-rectal pulsed irrigation device (18 patients) versus per-oral colonic lavage (15 patients). Colonoscopic preparation was assessed on a 0 to 4 plus scale by region and overall. This was done live and by video tape by two independent endoscopists who were blinded to the patient's preparation. There was no significant difference with respect to cleanliness of the colon with pulsed irrigation patients having an average overall preparation score of 3.00 +/- 0.19 (SEM) versus colonic lavage patients with a score of 3.14 +/- 0.19. There was also no statistically significant difference between the two groups with respect to demographics, time to reach the cecum, time for entire procedure, volume of aspiration or wash, or sedation given. We conclude that the new pulsed irrigation device provides an alternative to the standard per-oral lavage solution for colonoscopic preparation.