The investigators can find easily colon cancer and poly by colonoscopy, but bowel preparation is very important to find the lesion. Desirable bowel preparation drug must be clearly removed stool, effective on colonoscopic finding and pathologic finding, quickly administrated agent and eliminated stool, comfort for patient, and less side effects.~PEG is very safe osmotic laxative. New agent(coolprep) which add ascorbic acid is less salty and less volume. Picosulfate+magnesium citrate(picolyte) taste orange, can be easily prepared bowel for colonoscopy by good taste and small volume. Magnesium with citrate acts like osmotic agent, picosulfate acts irritant agent.~The investigators will compare with PEG+ascorbic acid and picosulfate+magnesium citrate about bowel preparation, patient's satisfaction, side effects to identify effectiveness of new bowel preparation drug.
The investigators will compare with PEG+ascorbic acid and picosulfate+magnesium citrate about bowel preparation, patient's satisfaction, side effects to identify effectiveness of new bowel preparation drug.