What to Expect on the Day of a Colonoscopy

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Before a colonoscopy, you will need to empty your bowels by taking laxatives. The outpatient procedure itself takes between 30 and 60 minutes. You'll receive medications to relax or sedate you, so you won't feel pain. After the test, you'll need someone to drive you home.

This article goes over what you need to know about what to expect before, during, and after a colonoscopy.

Woman in colonoscopy procedure room with medical staff
kzenon / iStock / Getty Images

Before the Procedure

Your colon has to be completely empty, not only to allow the scope to pass through the colon, but also to allow your healthcare provider the greatest visibility during the procedure. Proper preparation is important to ensure that your healthcare provider can detect any potential abnormalities inside the colon.

Arrange for someone to help you home once the procedure is complete, since the medications administered during this procedure can cloud your judgment and affect your reflexes.

Bowel Prep

Before the procedure, your healthcare provider will prescribe a colonoscopy preparation aimed at emptying the colon of fecal matter. Be sure to clear your schedule after noon of the day before the procedure and be close to a restroom during this time.

These instructions may include:

  • Avoiding high-fiber foods, including seeds and nuts, for up to a week prior to your colonoscopy.
  • Avoiding solid food for one day prior to the procedure (including absolutely nothing two hours before the procedure).
  • Drinking plenty of clear fluids the day before the test. Clear liquids include water, clear broth, coffee and tea (without milk), ice, or gelatin.
  • Avoiding red and purple liquids, which can be mistaken for blood in the colon during the procedure.
  • Drinking a strong laxative solution to empty your bowels the afternoon or evening prior to the procedure to clean your colon sufficiently for the procedure.

Sometimes drinking the laxative solution is more unpleasant than the actual colonoscopy procedure. Some people find refrigerating the solution and drinking it through a straw makes it easier to drink.

It is important to follow these instructions completely to ensure the procedure goes as smoothly as possible. Throughout the entire prep period, it’s also important to drink lots of fluids, because keeping hydrated not only clears your colon but helps to maintains your electrolyte balance.

During the Procedure

A colonoscopy may be performed at an outpatient center, clinic, or hospital. You will check in and change into a hospital gown.

An anesthesiologist or nurse anesthetist will give you a medication that makes you feel groggy. Your vitals, including your blood pressure, heart rate, pulse oximetry, and temperature will be monitored throughout the procedure.

The procedure is performed while laying on your side. A gastroenterologist uses a scope called a colonoscope to identify areas of bleeding or abnormal growth.

The colonoscopy procedure involves inserting a thin scope with a light on the end into the rectum. A small, non-painful burst of air is blown through the colon to widen the area. The gastroenterologist advances the scope through the colon to examine it.

They may remove samples of tissue for biopsy or remove an outgrowth of tissue known as a polyp. The entire procedure takes between 30 and 60 minutes. Rarely do people report feeling pain during a colonoscopy.

After the Procedure

You may feel groggy after the procedure due to the anesthetic that you're given just prior to your colonoscopy. For this reason, healthcare professionals recommend that you have a family member or friend pick you up after the procedure.

If the procedure is completed without complications, you should go home the same day. It's common to feel quite hungry after the procedure so you will be transitioned to solid foods soon after the procedure is complete.

While it’s normal to have some blood in your stool after the procedure, call a healthcare professional if you are concerned about blood in your stool or experience severe abdominal pain, as this may be indicative of a perforated colon, a very rare complication of the colonoscopy procedure.

If you experience unexplained weight loss, fever, chills, or anxiety as you wait for your results, do not hesitate to contact your gastroenterologist or healthcare provider.

Your healthcare provider will usually give you a preliminary result of your colonoscopy soon after the procedure. Your results can include:

If your results are normal, you will not need to have the procedure again for 10 years unless otherwise indicated. If a polyp is discovered, a biopsy is taken. It can take up to two weeks to receive your results. Normally, your healthcare provider calls you to communicate the results of your colonoscopy.

9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Library of Medicine MedlinePlus. Colonoscopy.

  2. National Institute of Diabetes and Digestive and Kidney Diseases. Colonoscopy.

  3. Sharma P, Burke CA, Johnson DA, Cash BD. The importance of colonoscopy bowel preparation for the detection of colorectal lesions and colorectal cancer prevention. Endosc Int Open. 2020;08(05):E673-E683. doi: 10.1055/a-1127-3144

  4. Liska D, Mah E, Brisbois T, Barrios PL, Baker LB, Spriet LL. Narrative review of hydration and selected health outcomes in the general population. Nutrients. 2019;11(1):70. doi: 10.3390%2Fnu11010070

  5. Sonnenberg A. Sedation in colonoscopy. Gastroenterol Hepatol (N Y). 2016;12(5):327-329. PMID: 27499716

  6. National Library of Medicine MedlinePlus. Polyp biopsy.

  7. National Institute of Diabetes and Digestive and Kidney Diseases. What Should I Expect After a Colonoscopy?

  8. Tiwari A, Sharma H, Qamar K, Sodeman T, Nawras A. Recognition of extraperitoneal colonic perforation following colonoscopy: a review of the literature. Case Rep Gastroenterol. 2017;11(1):256-264. doi: 10.1159/000475750

  9. American Cancer Society. American Cancer Society Guideline for Colorectal Cancer Screening.

By Shamard Charles, MD, MPH
Shamard Charles, MD, MPH is a public health physician and journalist. He has held positions with major news networks like NBC reporting on health policy, public health initiatives, diversity in medicine, and new developments in health care research and medical treatments.