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Bowel Preparation: Before Your Procedure

What is bowel preparation?

Bowel preparation (or bowel prep) empties and cleans out your large intestine (colon). Bowel prep is done before tests that look inside your colon, such as a colonoscopy. These tests look for small growths (called polyps), cancer, or other problems like bleeding. The colon has to be empty and clean so the doctor can see problems.

For many people, the bowel prep is worse than the test. The liquid you may have to drink can taste bad, and you may feel hungry on the clear liquid diet. You may also spend a lot of time in the washroom.

But it is very important to do the prep exactly as your doctor tells you to. If you do not, the doctor will not be able to see the entire lining of your colon. This may mean that you have to repeat the test and will have to do the prep again.

How do you prepare for the procedure?

Procedures can be stressful. This information will help you understand what you can expect. And it will help you safely prepare for your procedure.

Preparing for the procedure

  • 1 to 2 days before the test, you will stop eating solid foods and will drink only clear fluids, such as water, tea, coffee, clear juices, clear broths, flavoured ice pops, and gelatin (such as Jell-O).
    • Do not drink milk or juice with pulp, such as orange juice. These are not clear fluids.
    • Do not drink anything red, purple, or blue, such as grape juice or fruit punch.
    • Do not eat red, purple, or blue foods, such as grape Popsicles or cherry Jell-O.
    • Drink plenty of clear fluids to stay hydrated.
  • To clean out your colon and rectum you will need to drink large amounts of a bowel preparation (laxative) solution. The solution can taste bad and may make you feel sick to your stomach. But it is important to drink all of it or the doctor may not be able to do the test and you will have to do the prep and test again. Here are some tips:
    • After you drink a dose of the solution, drink some water or clear fluids to help get rid of the salty taste.
    • You may find it easier to drink the solution if you chill it in the refrigerator first.
    • Suck on lemon wedges after you take a drink.
  • Stay home the evening before the test. You will need to use the washroom often.
  • Do not eat any solid foods after you start the bowel prep.
  • You will be told which medicines to take or to stop before your procedure. Some medicines, such as aspirin or ibuprofen (Advil, Motrin), and certain vitamins and herbal remedies can increase the risk of bleeding or interact with sedation medicine you may get to help you relax. You may be asked to stop these before the test.

What happens on the day of the procedure?

  • Follow the instructions exactly about when to stop eating and drinking, or your test may be cancelled. If your doctor has told you to take your medicines on the day of the test, do so using only a sip of water.

At the hospital or clinic

  • Your doctor may have you use an enema 30 to 60 minutes before the test.

When should you call your doctor?

  • You have questions or concerns.
  • You don't understand how to prepare for your procedure.
  • You think you're having a problem caused by the bowel prep.
  • You become ill before the procedure (such as fever, flu, or a cold).
  • You need to reschedule or have changed your mind about having the procedure.

Severe reactions to the bowel preparation can happen, but it is rare. Call 911 or seek immediate medical attention if you:

  • Have vomiting that will not stop.
  • Feel like fainting.
  • Have swelling or hives (itchy red patches in your skin).
  • Have very bad pain in your abdomen (belly).

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