Computed tomography (CT) colonography has gained widespread multi-disciplinary interest as an evolving noninvasive colorectal screening examination, with the potential of improved patient compliance. The investigator's prior work demonstrated that the bowel preparation was the least tolerable aspect of colorectal evaluation when compared to the CT colonography and optical colonoscopy procedures. Stool tagging could provide a more gentle and efficient bowel preparation, with fewer false positives due to retained stool-mimicking polyps.