Cancer Institute A national cancer institute
designated cancer center

Clear Liquid Diet Guidelines


The clear liquid diet supplies fluids and energy from foods that require very little digestion. This diet is often used in preparation for surgery and lower endoscopy procedures. The clear liquids reduce bowel residue and provide fluids to ease thirst. These liquids also provide certain salts and minerals and prevent dehydration.

It is important that the clear liquid diet be followed exactly.  Remember that the value of the examination will depend on getting a thoroughly clean bowel.


A clear liquid diet is not adequate in calories and nutrients.  It should not be followed for more than five days unless supplemented by high-protein gelatin or other low residue supplements.

Allowed and Recommended Foods

Do not drink or eat anything with red or purple coloring.  Red/purple food coloring can leave a residue in the bowel that resembles blood.  Keep this in mind when purchasing Jell-O, Popsicles, hard candy, drinks, etc.

No solid foods allowed, including milk/milk products. 

If you have any questions or concerns, call the nurse coordinator at (650) 725-9772.

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