When I did my last colonoscopy prep recently, I found alternating sips of a sweet drink like applejuice along with liquid prep made me have less nausea and it worked out well. I even pinched my nose a bit so as not to taste the prep so much. Maybe this would help you too. I get polyps in my colon so a colonoscopy is a necessity to have them removed. Give it another try, telling yourself you have to do this for your own health. Good luck to you!