The key to a successful colonoscopy is proper intestinal preparation. This is quite normal and indicates that the moviprep solution is working. Pin On Tmi Bowels return to normal in a day or two. How long does moviprep take to work . Is that normal or does it mean it's not worked? 4, after procedure you can eat but keep diet light for rest of day. Any bloating is wind that will pass out normally. Moviprep can start working quickly and watery bowel movements are normally seen for at least two hours, however the effects can last a lot longer. At 8am take moviprep again as per above with 2l or more of water. A watery bowel movement should begin in approximately two hours after you finish drinking the first liter of moviprep solution. Moviprep comes with instructions about when and what to eat or drink on your first day of treatment. Use cream on your bottom from the start and use a pad on the way home,as you might have some leakage!! How long does diarrhea last w...