Medical staff typicallyrecommend that 3 days before a colonoscopy, a person should avoid: 1. nuts 2. seeds 3. corn, including popcorn Also, drink plenty of clear liquids and avoid anything with red, blue, or purple dyes. These colorings can make it seem as if there is blood in the colon. Some examples of liquids that are OK to drink include: 1. pul...

The day before a colonoscopy, people should not have solid food. A person can have unlimited amounts of clear liquids and those in the list above. Usually, a person starts drinking the prep solution at this time. Healthcare staff tend to recommend having half the night before and half on the morning of the colonoscopy.

A person continues to have only clear liquids and no solid foods. By this point, they should be using the toilet regularly, and their stools should be clear. Remember to stay hydrated. The preparation essentially involves giving a person diarrhea, so it is important to drink plenty of fluids until 2 hours before the procedure.