Colonoscopy Preparation

Colonoscopy Preparation

A colonoscopy is a thorough examination of the large bowel using a flexible tube that transmits a live, color image onto a screen. Clearing your colon is essential for optimal visibility. Follow these instructions carefully for a successful and positive experience during the procedure. A nurse will contact you before your procedure to review your health history, medications, preparation instructions and address any questions you may have.

Download a PDF of the Colonoscopy Preparation Instructions


  • You will be asked to hold your vitamins and supplements 1 week before your procedure.
  • If you have diabetes, certain diabetic medications may be adjusted prior to your procedure.
  • If you are on blood thinners, such as Warfarin, Clopidigrel or Aspirin, please ask your provider
    for instructions on how to manage your blood thinner prior to your colonoscopy at your
    physical assessment appointment.

Shopping List

All items can be purchased over the counter, no prescription needed.

  • Clear liquids: clear juices (like apple and white grape), green or yellow Jell-O, black coffee,
    tea, soda, broth (chicken, beef or vegetable), lemon ice, and plenty of water.
    *No liquids with red dye in them
  • 56 ounces of an electrolyte drink like Gatorade, Propel, Powerade or other clear
    liquid (generic is fine). If diabetic, use Propel.
  • Dulcolax (Bisacodyl) laxative (5 mg) tablets. You will need 4 tablets.
  • Miralax or generic equivalent (238g) bottle of powder



Pick up your prep kit at the CRMC pharmacy!


3 Days Before Your Exam

  • Your preparation starts three days before exam.
  • We recommend cutting back on the amount of food you eat and encourage drinking more water starting 3 days before your exam and continuing until cleanse day (when you will do only clear liquids).
  • Avoid foods with seeds, nuts and fruit with skins. These are more difficult to clear out of your colon.
  • Being well hydrated will help you feel better, make the IV start easier, and help the cleanse to be more effective.
  • It varies from person to person how quickly the prep starts working, but the desired result is that your stools should look like clear colored liquid without any formed stool, pieces, or particles present.
  • Inform your nurse on arrival if you feel the prep has not worked properly.

The Day Before Your Exam (Cleanse Day)

Diet – Clear liquids only all day – No solid food
  • It is important that you drink as much clear liquid as you can throughout the day.
  • Remember no food on the cleanse day. No liquids with red dyes. No orange, grapefruit, or prune juice.

3:00 pm: Take 4 of the Dulcolax (Bisacodyl) laxative tablets by mouth (5 mg each for a total of 20mg).

6:00 pm: Mix 238 grams of Miralax (PEG3350) into 56 oz. of an electrolyte drink. Mix until fully dissolved, then refrigerate. Drink one 8 oz. glass of solution every 15 minutes until HALF of the solution is gone.

4 hours before your scheduled arrival time for your colonoscopy, drink one 8 oz. glass of solution every 15 minutes until entire container is consumed.
*Do not drink anything more after you complete this portion of the preparation.

  • It is important to finish the entire mixture. An inadequate cleanse may require the colonoscopy being rescheduled.
  • If you have had bariatric surgery (gastric bypass, Roux-en-Y, gastric diversion or gastric sleeve) you may need to extend your time between drinks.
  • If you have any questions, please call the Perioperative Medicine Clinic 218-546-2375.

Double- or Two-Day Prep

If you are asked to do a “double- or two-day prep”: You will need to purchase 2 sets of the bowel prep materials on the shopping list.

  • 2 days before the day of your exam: clear liquids only – all day long
  • 3:00 pm: Take 4 of the Dulcolax (Bisacodyl) laxative tablets by mouth (5 mg each for a total of 20mg).
  • 6:00 pm: Mix 238 gm bottle of Miralax with 56 oz of electrolyte drink. Drink 8 ounces of the mixture every 15 minutes until gone.
  • The day before your exam: Follow “the day before your exam (cleanse day)” section above.

Day of Colonoscopy

  • Shower, wear clean, casual clothes to the hospital. Do not apply any hair products, perfume, lotions, creams, or powders. This includes prescription lotions or creams. Please remove all piercings and jewelry.
  • Please be sure to have a driver to bring you home. Without a driver, your procedure will be cancelled or rescheduled.
  • You must arrange for a responsible individual to accompany you for transportation after the procedure. If using ride share, taxi, or bus, ensure the presence of a responsible person other than the driver. Options for transportation include VA services, Medivan, church groups, or volunteer drivers. This is not only for your safety but also for the safety of others on the road. Driving after sedation is against the law, and having someone with you ensures a safe entry into your home.
  • It is also recommended that someone stay with you for 24 hours after the procedure for your safety.
  • Be sure to take your medications as directed the day of the procedure.
What to Bring with You to the Hospital
  • Insurance and prescription cards along with a photo ID. Please be prepared to purchase any medication if prescribed after your procedure.
  • Glasses and/or contact case.
  • Hearing aids.
  • A friend or relative to receive discharge instructions and drive you safely home.
What to Leave at Home
  • We encourage you to leave all valuables at home.
  • The hospital is not responsible for lost or damaged valuables.
When You Arrive
  • Park in the main parking lot and enter through the main entrance.
  • Check in at the multi-specialty clinic registration/surgery registration just past the coffee shop
After Your Colonoscopy
  • You may not operate any motorized items (automobile, ATV, snowmobile, machinery) or sign any legal documents following the administration of sedation/anesthesia.
  • We recommend you do not return to work the day of your procedure.

Any questions OR changes in your health prior to your procedure: You may contact the pre-op education nurse at 218-546-2375 between the hours of 8 a.m. and 4:00 p.m., Monday through Thursday and 7 a.m. to 4:00 p.m. on Fridays. After hours, and on the weekends, you may call the Medical Center at 218-546-7000, or toll free at 888-487-6437, and ask to speak with the charge nurse. We are available to answer your questions and would be happy to speak with you.


Colonoscopy Preparation & Diabetes

The below are general guidelines for diabetes. Please call the health care provider who manages your diabetes if you have additional questions. For people with diabetes, any medical test that causes you to miss a meal or change your usual meal plan will require planning to keep your blood sugar numbers from becoming too high or too low.

  1. Test your blood sugar: before meals and bedtime, on preparation day and the morning of the colonoscopy test. Test your blood sugar if you are feeling that you might be too high or low. If you are unaware of your low sugar symptoms, test every two or three hours. Blood sugar may or may not return to your usual numbers for up to 72 hours after the colonoscopy.
  2. If you have a low blood sugar on preparation and/or test day, you must treat it with one of the following: four or five glucose tablets (non-red or purple), 1/2 cup white grape juice, or 1 cup real soda(15 gr of carb) and test your blood sugar more times than usual during the day while trying to keep blood sugar numbers between 100 and 200mg/dl. If low blood sugar persists, contact your health provider for guidance.
  3. Bring your diabetes supplies. Such as glucose tablets or another sugar source, with you to the colonoscopy test. Be sure to tell the staff if you are experiencing any low blood sugar symptom.
  4. During the preparation day (day before the test), drink both sugar free and sugar containing drinks (see below for options and menus).
  5. On procedure day: do not have anything by mouth after the second half of the prep. If you have low blood sugar during “nothing by mouth time”, use glucose tablets or take 1/2 cup 7up or juice box.
  6. Replace usual meals with 45-60 grams of liquid carbohydrate or 1 1/2 cups to 2 cups. Liquid carbohydrate is absorbed in the stomach more rapidly and could increase the chance of low blood sugar. Follow insulin dosing for carbohydrate liquid meals as recommended by your provider.
  7. Examples of sugar containing clear liquids (or 15 grams of carbohydrate) to be used for meals or a snack:
    A. Apple or white grape juice 1/2 cup = 15 grams E. Gatorade 1 cup = 15 grams
    B. Jell-O (non-diet) 1/2 cup = 15 grams F. Kool-aid 1/2 cup = 10 grams
    C. Popsicles 1/2 cup = 15 grams G. Clear Boost 1/2 cup = 18 grams
    D. Regular soda 1/2 cup = 15 grams H. Clear Ensure 1/2 cup = 16 grams
  8. On the procedure day (until 4 hours before you are instructed to arrive), if you have some clear liquids, mix them with an equal amount of water. Then NOTHING more orally until after the procedure is completed.
  9. Some clear liquids include:
    A. Fat-free broth, bouillon, or consommé D. Seltzer and flavored water
    B. Diet clear soda E. Resource Breeze – 10-gram protein drink
    C. Coffee or tea, unsweetened or diet



Apple or white grape juice (1 cup)
Regular sweetened gelatin (1 cup)
Resource breeze (1 cup)
Tea with lemon (1/2 cup)


Consommé or broth (3/4 cup)
2 Orange popsicles (1 cup)
Italian Ice (1/2 cup)
Regular gelatin (1/2 cup)


Consommé or broth (3/4 cup)
Clear juice (1 cup)
Regular gelatin (1 cup)
Tea with lemon (1/2 cup)