 The patients, attending physicians, endoscopists, data assessors and data analysts will all be blinded to the patients allocation. Allocation will be kept at a central location and will be known only to the person who will randomize patients. On the day of colonoscopy all patients will be accompanied with a trial form where all relevant data will be entered. First part will be filled by the attending physician who refers the patient to colonoscopy, the second part will be filled by the endoscopist and the third part will be filled by trial associates on the day of discharge appendix 1. 