Colonoscopy Prep Diet

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If your doctor has ordered you to undergo a colonoscopy so she can better determine the health of your rectum and colon, she will probably also advise you to follow a colonoscopy prep diet to help you clean out your bowels before the exam. A colonoscopy prep diet is a special diet that you eat for a specific period of time before your exam to help your body release fecal matter and residue from your intestines and rectum. Although specific guidelines exist for a colonoscopy prep diet, speak with your doctor so she can alter the plan to ensure that your individual dietary needs are met throughout the diet.


A colonoscopy is a medical examination used to detect abnormalities in your rectum or colon, such as abnormal pre-cancerous or cancerous growths, ulcers and inflamed tissue. A colonoscopy prep diet is a pre-treatment regimen used to empty fecal matter and residue out of your colon and rectum to ensure that the medical professional performing your colonoscopy has an unobstructed view of your rectum and colon during the exam, according to the Mayo Clinic.


You should begin to eat light foods such as eggs, clear soups, skinless potatoes, steamed white fish, cheese and skinless chicken three to four days before your exam, according to the Colon Cancer Resource Center. Then, the day before your exam, you should eat a light breakfast such as toast and eggs, and then begin an all-liquid diet for the rest of the day. The recommended liquids that you should drink that day include water, strained fruit juices, clear soup broths such as chicken broth, vegetable broth or fish broth, ginger ale and sports drinks such as Gatorade.


Foods to Avoid

You should avoid foods with red dyes and liquids, such as red gelatin desserts, red fruit juices and red soft drinks. The red dye in these foods and beverages can show up as blood during your colonoscopy, which could give your doctor erroneous information while she is determining the results of the examination, warns the Mayo Clinic.

Additional Preparatory Suggestions

Your doctor may also ask you to take a laxative or enema the night before, or morning of your colonoscopy to ensure that all fecal matter and residue are removed from your rectum and colon, according to the National Digestive Diseases Information Clearinghouse.



You should alert your doctor of any prescription medications you are taking prior to your colonoscopy to ensure that she has enough time to adjust your medications as necessary before your exam to avoid any medical emergencies that could arise from you not taking your needed medications. You should also tell your doctor if you have any special dietary needs that need to be addressed during your colonoscopy prep diet before you begin the diet.


Is This an Emergency?

If you are experiencing serious medical symptoms, please see the National Library of Medicine’s list of signs you need emergency medical attention or call 911. If you think you may have COVID-19, use the CDC’s Coronavirus Self-Checker.