Reader Question: “Is it okay to sip water after midnight the night before my colonoscopy, or is that a no-go? I always keep a glass of water next to bed and drink a bit throughout the night."

Thank you for this question. Drinking water is highly encouraged while preparing for a colonoscopy as it helps mitigate the dehydrating effects of the preparation process. However, even water becomes unsafe if taken too close to the procedure. Currently, the consensus within the medical community is to stop taking all clear liquids, including water, about 3-4 hours before your procedure. So, if your colonoscopy is scheduled for the late morning or afternoon, drinking water through the night should be fine. However, it might be best to use midnight as the cutoff time for early morning appointments.

While I understand that your preference to drink water during the night, doing so too close to your procedure could be harmful. For one, it may reduce the visibility of your colon and force your doctors to cancel the procedure. Another concern is the risk of aspiration, which involves the content of the stomach being regurgitated and inhaled into the lungs. Both these outcomes are thoroughly undesirable, so, stopping water intake at the right time is key.

Ultimately, your doctors have the final say on this since they know your complete medical history and can advise you more holistically. For example, patients with diabetes may be permitted sips of water close to the procedure because of their increased risk of dehydration.