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Colonoscopy and Flexible Sigmoidoscopy

Your doctor has requested a colonoscopy (cohl-on-OSS-coh-pee) or a flexible sigmoidoscopy (sig-moyd-OSS-coh-pee) for you. A colonoscopy is an exam of the inside of your large intestine (colon). A flexible sigmoidoscopy is an exam of only the lower section of the large intestine (sigmoid colon). See diagram below.


Following are general guidelines for these tests. You will receive more specific instructions from your doctor, nurse, or testing center.

Preparing for a colonoscopy or sigmoidoscopy

Plan for Getting Home

Arrange for a responsible adult to drive you home and stay with you after your test.



Please check with your doctor or testing center for instructions if you are taking any of the following medications:

  • Heart medication
  • Aspirin
  • Coumadin®
  • Iron products
  • Iron medication
  • Antacids
  • Over-the-counter medication
  • Nonsteroidal, anti-inflammatory drugs (Advil®, Motrin®, ibuprofen, or arthritis medication)
  • Diabetes medication (insulin, Glucophage®, or others)


Your doctor may tell you that you can have only clear liquids the day before your test. Do not eat or drink anything after midnight the night before your test.

Special Preparation

  • For a colonoscopy, you will be given a laxative to drink. This cleans out your colon and gives the doctor a better view during your test.
  • For a sigmoidoscopy, you will receive instructions for giving yourself a bowel
    preparation to help clean out your lower colon.
  • Your doctor will decide which preparation is best for you.

The day of the test

Please Bring:

  • Your prescription
  • An insurance card and/or referral form
  • A list of your medications and allergies
  • A responsible adult to drive you home and stay with you,if you receive a sedative. 


What will happen before the tests?

  • You will sign a consent form for the test.
  • You will change into a hospital gown.
  • An intravenous (IV) line may be started in your arm.
  • You may be asked to remove glasses, contact lenses, dentures, and jewelry.


What will happen during the tests?


You will lie on your side with your knees drawn toward your chest so you are more comfortable. Your blood pressure, pulse, breathing, and blood oxygen levels will be monitired during the test. You will receive a medication through your IV to help you relax. The doctor will insert a long tube called a colonoscope (ko-LON-ohscope) into your rectum and move it through your colon. He or she will fill your colon with air. This will help the doctor get a better view. The air may give you some discomfort or pressure. This feeling is normal and should go away soon after the test. The test usually takes between 20 and 30 minutes.



You will lie on your side with your knees drawn toward your chest so you are more comfortable. The doctor will insert a flexible tube called a sigmoidoscope (sig-MOY-dohscope) into your rectum and lower colon. You may feel some discomfort as the tube moves into your colon. This test usually takes about 15 minutes.

How will I feel after these tests?

After these tests, you may feel groggy from the medication. You may also feel bloating or cramping from the carbon dioxide that was inserted. This feeling will go away after you let the air back out. 


What should I report to my doctor?

Call your doctor immediately if you have:

  • Persistent rectal bleeding
  • Persistent or severe pain
  • Temperature of 100°F or above
  • Black, tar-like stools

You will receive specific instructions from your nurse and/or doctor upon discharge.

Getting your test results

Your doctor will discuss the results of your test with you. Please talk with your doctor and/or testing center about how to get your test results.


If you have further questions, call:



What I need to do:

  • Schedule an appointment at ______________(place) on ____________________ (date).
  • Report to at ___________________(time).
  • Receive specific instructions: ______________________________________________
  • Bring your prescription, insurance information, and/or a referral slip.
  • Bring a list of your medications and allergies.
  • Arrange for transportation with a responsible adult driver.
  •                                                                                                                          Revised July 2013

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