Is it necessary to fast the day before a colonoscopy?

The day before a colonoscopy, it is necessary to avoid any solid foods, alcohol and dairy products, according to Palo Alto Medical Foundation. Eating solid foods is likely to result in the procedure being cancelled.

Clear liquids, such as water and apple juice, are allowed, as are black coffee, broth and jello, notes Palo Alto Medical Foundation. Cardiac and blood pressure medications, acetaminophen and most other normal medications may be taken. Aspirin and NSAIDs, such as ibuprofen and Aleve, should be avoided the week before the procedure. It is okay to continue a clear liquid diet the day of the procedure unless otherwise instructed.