Your doctor has suggested that you have a colonoscopy as part of your evaluation at National Jewish Health. A colonoscopy allows the doctor to look inside the colon, or large intestine, using a small flexible tube. Your doctor may also do a biopsy and remove any polyps (small growths) he/she finds during the procedure. A biopsy is a small amount of tissue taken from the lining of your colon which can be studied closely to help determine your diagnosis and how best to treat you.

Video: What to Expect From Your Colonoscopy Procedure

Preparing for the Test

Your colon will need to be cleaned thoroughly to complete the test. If this is not done correctly, the test will need to be rescheduled.

The medicines you receive during the colonoscopy will make you sleepy. Ask someone you know to accompany you on the day of your procedure and to drive you home afterward. If you do not have someone to drive you home, the procedure will be cancelled. Your ride needs to be someone you know over 18 years of age, or a medical transport. It is a good idea to have someone with you for the remainder of the day and night. You will not be able to work, drive, or make any decisions for the rest of the day. You will not be allowed to use public transportation unless you are accompanied.

If you use oxygen at home when you sleep and/or when you are active, please bring your portable tank with you. You may need to use the oxygen for a while after the procedure.

Avoid Metamucil and any foods with skins (tomatoes, apples), seeds, corn or nuts for a few days before your test.

Follow These Instructions Carefully

  • Inform your doctor of all the medicines you take. You may be given specific instructions about certain medicines.

  • Notify your doctor if you take any blood thinners such as Coumadin, Plavix, Lovenox, Pradaxa, Xarelto etc.

  • Stop any iron-containing medicines or supplements 7 days before the colonoscopy.

  • Inform your doctor if you take any oral medicines or insulin for diabetes.

  • Purchase a supply of clear liquids for the day before the test. These include Gatorade, fruit juices (no citrus), soda, popsicles without fruit or cream, gelatin without fruit, broth (skim the fat off the top), and black coffee or tea. Do not drink anything that is red, orange or purple.

Do the Preparation

Day of the Test

  • Do not eat or drink anything except as directed.

  • Take only the medicines the doctor has asked you to take. They should be taken after you have finished the solution.

  • Bring your inhaled medicines with you.

  • If you have sleep apnea, bring your CPAP mask and machine with you.

  • If you are diabetic, please bring your glucose meter, test strips, and fast acting glucose source (either glucose tablets or gel).

  • Bring extra clothing, just in case you need it.

  • Check in at the “check-in desk” in the front lobby at the specified time.


During the Test

When you arrive, the nurse will explain the procedure before, during, and after the colonoscopy. If you have any questions, please ask. The nurse will start an IV to administer sedation used during the procedure. You will be monitored closely during the procedure. You will be asked to lie on your left side. You may feel some pressure and cramping, but most people have no memory of the actual procedure. Once the procedure is completed, you will be taken to a room to recover. You will feel a little sleepy. Your doctor will determine when you are able to go home.

Length of Test

Please plan on being at National Jewish Health for at least 3 hours. The procedure only takes about 20 minutes, but you will need to recover before you can go home. Remember, you will need someone to drive you home. You will need to plan on resting the rest of the day.

Please call 303.398.1355, option #4 if you have any questions or need to change the time or cancel the appointment.


This information has been approved by Jeffrey King, MD (April 2022).