Protocol issues. Modifications potentially will be undertaken and resubmitted to IRB

This will be a 4-way comparison to prospectively evaluate the efficacy and patient tolerability of four commercially available bowel preparations among patients undergoing colonoscopy for screening and surveillance in a single tertiary academic medical center.

We will randomize 300 consecutive patients undergoing colonoscopy for screening or surveillance purposes to receive one of four bowel purgatives. These purgatives include

1. Split dose 4 liter polyethylene glycol with electrolytes (PEG+E): Brand name GoLytely
2. Split dose 2 liter polyethylene glycol with ascorbic acid (PEG+Asc): Brand name: MoviPrep
3. Split dose sodium picosulfate, magnesium oxide, and anhydrous citric acid (P+MC): Brand name Prepopik
4. Split dose sodium sulfate, magnesium sulfate, and potassium sulfate solution (sulfate): Brand name Suprep

Inclusion Criteria:

1. Age 18 years or greater
2. Ability to understand and complete questionnaires
3. Ability to speak and read English
4. Willingness to participate in study
5. Colonoscopy is being performed for routine screening (i.e. no prior personal history of polyps or cancer) or surveillance (i.e. follow up for a personal history of polyps) purposes

Exclusion Criteria:

1. Previous bowel resection of any kind (small or large bowel)
2. End stage renal disease (ESRD)
3. Contraindication to bowel purgative
4. Necessity for inpatient admission to receive bowel preparation for any reason
5. Currently taking any narcotic/opiate pain or anticholinergic medication (since these may predispose to higher colon stool burden at baseline)
6. Currently taking stool softeners (e.g. Miralax, Amitiza, Linzess, lactulose) or stimulant laxatives (e.g. Dulcolax)
7. Subject did not follow appropriate dosing instructions for bowel purgative
8. Colonoscopy is being performed to evaluate a clinical symptom such as rectal bleeding, constipation, abdominal pain, or diarrhea
9. History of colon polyposis syndrome
10. Personal history of inflammatory bowel disease
11. History of inadequate colon preparation on any prior colonoscopies
12. Patient is pregnant