What to Eat & Not Eat in Preparation for a Colonoscopy

A colonoscopy is a procedure that examines the inside of your colon. Prior to examination, your doctor may recommend that you consume certain foods while avoiding others to ensure a successful procedure. A clear liquid diet is typically recommended one day before the procedure. Consult with your health care provider for a full list of colonoscopy preparation instructions 1.


During a colonoscopy, a flexible instrument known as a colonscope is inserted through the rectum to examine the inside of the colon. The doctor looks for early signs of colorectal cancer or any unexplained changes in your bowel. The procedure also enables a doctor to evaluate and detect inflamed tissues, ulcers, abnormal growths and intestinal bleeding. The entire procedure takes 30 to 60 minutes and you should fully recover by the next day.

Preparation Diet

The day before the procedure, your health care provider will recommend to begin a clear liquid diet. A clear liquid diet is intended to clear the gastrointestinal tract of any solids. Clear liquids are easily absorbed and will provide vital fluids for the body prior to surgery. A clear liquid diet does not provide all the essential nutrients and as such, you should only follow it for a short period of time. In addition to a liquid diet, your health care provider may recommend an oral laxative to increase bowel movements and further empty the bowel.

What to Eat

Clear liquids include anything you can see through. Examples of acceptable clear liquids include water, soft drinks, plain coffee, herbal teas and electrolyte sport drinks. Other clear liquids include fat-free chicken or beef broth, gelatin, ice pops and clear hard candy. Fruit juices such as apple, grape and cranberry without pulp are also acceptable clear liquids. You can add sugar, salt and lemon to your liquids to improve flavor. Ask your health care provider about clear liquid nutritional supplements.

What Not to Eat

In general, avoid all solid and fibrous foods. You should also avoid milk, juices with pulp, meat and vegetable soups and mixed drinks. Additionally, you should avoid all beverages and foods that contain artificial red or purple dyes as these dyes mask the lining of the colon.