It is recommended to take Dr. Tobias Colon 14 Day Cleanse at bed-time with a large glass of water.  We understand some people such as shift workers may need to take it in the day time, which is why we do not say "night" time.  The product will work best while you are sleeping as this is when your body goes into a natural state of restoration.  Taking it in the daytime while you are up and active may not produce the results you want, however, you can certainly try it and see if it works for you.