I also am having a colonoscopy in 2 weeks. I don't want to go through the harsh purge either. Does a colon irrigation, colonic, clean out the entire colon or just the sigmoid and rectom? Never had one done. I think that I am going to do the liquid diet for 2 days and then do Miralax with gatorade the day before. Your supposed to take Dulcolax tabs with that prep but I heard Dulcolax is very harsh.