Is a clear liquid diet required for a colonoscopy?

Doctors often ask patients to follow a clear liquid diet before a colonoscopy, according to the Mayo Clinic. The patient must follow this diet on the day before the exam as well as take a laxative to clear out the bowel.

The Mayo Clinic gives the following advice to patients following a clear liquid diet in preparation for a colonoscopy: drink water, clear carbonated beverages, broth, and tea or coffee without milk, but avoid red liquids, which can look like blood during the test. Patients should always follow their doctors' instructions about drinking, eating and taking medications before a colonoscopy.