This study will evaluate whether morning-only dosing of MoviPrep® (2L) for afternoon colonoscopy is as effective as a standard dosing regimen of half of the volume of MoviPrep® (1L) solution the evening prior, and half (1L) the morning of, colonoscopy. MoviPrep® is a low volume (2 liters) polyethylene glycol (PEG)-based purgative that is approved for evening-only or split (evening and morning) dosing to cleanse the colon prior to colonoscopy. Patients undergoing afternoon colonoscopies often have inferior colon cleansing. There is evidence that morning-only purgative administration of large volume PEG (4L) is safe and effective. This study will assess whether administration of a low volume PEG regimen will maintain efficacy and improve tolerance by changing a 2-day preparation procedure into a regimen that is completed in 1 day.