I Want To Have A Colonoscopy But Don't Want To

I want to have a colonoscopy but don't want to destroy my beneficial bacteria that i have been so intent on protecting with the polyethylene glycol. someone told me to do a colonic instead but the doctor insists on using the prep although he said i could use the one called Nulytely which doesn't seem to have artificial sweetener in it....
do you think the polyethylene glycol will mess up my flora?
thanks