Published on September 22, 2025 4 min read

What to Expect During a Colonoscopy: Preparation & Procedure

A colonoscopy is a medical procedure used to examine the colon (large intestine) for abnormalities such as polyps, inflammation, or cancer.
It is a crucial screening tool for detecting colorectal cancer early when treatment is most effective.

Understanding what to expect before, during, and after a colonoscopy can help ease anxiety and ensure a smooth procedure.
This guide will walk you through the preparation process, what happens during the procedure, and what to expect afterward.

How to Prepare for a Colonoscopy

Dietary Restrictions

One to three days before the procedure, you may need to switch to a clear liquid diet, including broth, clear juices, and water.
Avoid solid foods, dairy, and anything with red or purple coloring.

Bowel Preparation

Your doctor will prescribe a laxative or bowel prep solution to clear your intestines.
Follow the instructions carefully, as a clean colon is essential for an accurate exam.

Medication Adjustments

Inform your doctor about any medications you are taking, including blood thinners, diabetes medications, and supplements.
You may need to stop or adjust certain medications before the procedure.

What Happens During a Colonoscopy?

Arrival & Sedation

Upon arrival, you will change into a hospital gown, and a nurse will start an IV for sedation.
Most patients receive either mild sedation (to help them relax) or deep sedation (to make them sleep through the procedure).

The Procedure

A flexible tube with a camera (colonoscope) is gently inserted into the rectum and advanced through the colon.
The doctor examines the colon lining, looking for polyps, inflammation, or other abnormalities.
If polyps are found, they can be removed during the procedure and sent for biopsy.

Duration

The procedure usually takes 20 to 45 minutes, depending on findings and whether polyps need removal.

What to Expect After a Colonoscopy

Recovery

You will rest in a recovery area until the sedation wears off.
Some drowsiness, bloating, or gas is normal.
Arrange for someone to drive you home, as you should not operate machinery for 24 hours.

Results

Your doctor may discuss initial findings right away, but biopsy results (if taken) may take a few days.
If polyps were removed, follow-up tests or lifestyle changes may be recommended.

Resuming Normal Activities

You can return to a normal diet and activities the next day, unless instructed otherwise.
Avoid heavy meals and alcohol for the first 24 hours.