When to Start a Clear Liquid Diet Before a Colonoscopy?

A colonoscopy is an internal exam of your large intestine, or colon, as well as your rectum. An instrument known as a colonoscope is inserted into your anus to examine your bowels. To prepare for a colonoscopy and to help ensure accuracy of your exam, you will need to completely cleanse your intestines. Your doctor will provide specific instructions on how to cleanse your intestines. This preparation will include a clear liquid diet.

Prep Time

The preparation time for a colonoscopy varies based on the individual patient and the rules of the hospital or facility where you will have the colonoscopy. The National Institutes of Health indicate a clear diet may occur one to three days prior to your test.

Clear Liquid Diet

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A clear liquid diet consists of foods and drinks that are liquid and transparent while at room temperature. Fluids should be clear enough so that you can see through them, according to Johns Hopkins Medicine. A clear liquid diet completely clears your colon of stool and other fluids, while providing hydration and some energy. It is important to check with your doctor if you have questions regarding the types of clear liquids you are able to consume. For instance, you may be asked to avoid gelatin, hard candies and cranberry juice. These products may be mistaken for blood during a colonoscopy.

Clear Liquid Foods

While on a clear liquid diet you are permitted to drink water, juices without pulp, coffee or tea without milk or cream, non-carbonated, powered beverages and clear sodas such as ginger-ale. You can consume clear broths, including chicken or beef. Clear gelatin, fruit ices and popsicles without pieces of fruit are also permitted. You are permitted to consume clear, hard candies and add salt, pepper and sugar to your foods and drinks.

Other Preparation

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A clear liquid diet is normally not the only form of preparation you will be required to participate in prior to your colonoscopy. You will likely be told to stop taking blood-thinning medications -- including aspirin, ibuprofen and naproxen. You may also be instructed to consume polyethylene glycol the evening prior to your colonoscopy -- an electrolyte substance to help the output of your bowels run completely clear. You may also be asked to take laxatives or an enema to help clear out the intestines.