How you prepare

Before a barium enema exam, you'll be instructed to empty your colon. Any residue in your colon may obscure the X-ray images or be mistaken for an abnormality.

To empty your colon, you may be asked to:

• Follow a special diet the day before the exam. You may be asked not to eat and to drink only clear liquids — such as water, tea or coffee without milk or cream, broth, and clear carbonated beverages.
• Fast after midnight. Usually, you'll be asked not to drink or eat anything after midnight before the exam.
• Take a laxative the night before the exam. A laxative, in a pill or liquid form, will help empty your colon.
• Use an enema kit. In some cases, you may need to use an over-the-counter enema kit — either the night before the exam or a few hours before the exam — that provides a cleansing solution to remove any residue in your colon.
• Ask your doctor about your medications. At least a week before your exam, talk with your doctor about the medications you normally take. He or she may ask you to stop taking them days or hours before the exam.