ClearFast is a preop drink that safely hydrates and nourishes before procedures like surgery and colonoscopy. Optimize your anesthesia experience by drinking ClearFast and benefit from an enhanced recovery after surgery.Drinking ClearFast PreOp drink prior to your medical procedure is a safe way to speed up recovery time, nourish your body preop, and reduce postop nausea and vomiting. Research shows a patient entering surgery starved and dehydrated is the way of the past. Preparing for surgery with a clear, complex-carb rich preop beverage will keep you strong and enhance your recovery.