When I had my colonoscopy a few months ago, I drank coconut water. I had a go ahead from my doctor and I really liked the taste. Just to be clear I am referring to the coconut water not the coconut milk. I had a tip which I would like to share, I did not use any toilet paper or wipes, since we do not have a bidet, I filled up water bottles with luke warm water and wash with dove and water instead of wiping then damp dry with a towel. It saved me a lot of irritation which is very important to me since I have 2 setons. I hope your colonoscopy goes well.