Colonoscopy is usually associated with coiling ("looping") of the colonoscope (instrument used for the procedure) in parts of the bowel. This is the main reason for patient discomfort and lengthens the duration of the procedure. Minimizing the coiling of the colonoscope would decrease the duration, and improve the efficiency and tolerability of the procedure and have a positive impact on colon cancer screening.

The primary aim of this study is to compare the time it takes for the colonoscope to reach the end of the colon when the patient is lying on the belly versus the left side (usual) at the start of the procedure. Patients who have medical conditions that may be affected by lying on their belly or those who cannot comfortably lie on the belly will be excluded from the study. Changes in patient position and use of abdominal pressure (commonly given by the endoscopy nurse during the procedure) will be permitted as necessary and determined by the endoscopist. The endoscopist will also retain the decision to discontinue the patient's participation from the study for any medical reason. After the procedure the patient will be monitored in the usual manner and asked to fill out a "satisfaction survey" (24 hours after).