Poor bowel preparation and patient intolerance of the procedure are the most important factors contributing to the limitation of colonoscopy. Inadequate bowel cleansing results in incomplete testing, increased potential to miss lesions, increased cost, and decreased patient satisfaction. The investigators hope to gain better insight into which bowel preparation works best in diabetic patients and hence would increase patient satisfaction, tolerability of the bowel preparation and decrease overall costs. The investigators will investigate which bowel preparation for colonoscopy will work optimally in diabetic patients using three different regimens.