Search the Health Library
Get the facts on diseases, conditions, tests and procedures.
I Want To...
I Want To...
Find Research Faculty
Enter the last name, specialty or keyword for your search below.
School of Medicine
A colonoscopy is an endoscopic procedure used to detect changes or abnormalities in the large intestine. Your doctor uses a long tube called a colonoscope, and the procedure takes approximately 30 to 60 minutes.
A: Position of the colonoscope in the colon; B: endoscopic view;
C: detail of the colonoscope tip
A colonoscopy allows your gastroenterologist to obtain detailed images of your colon in order to diagnose your digestive condition. A colonoscopy is an outpatient procedure, so you go home the same day.
Colonoscopy: Why It’s Performed
A colonoscopy is a standard procedure used to help diagnose a variety of gastrointestinal conditions.
Your doctor may recommend colonoscopy for:
- Changes in your bowel habits
- Blood in the stool
- Unexplained anemia
- Screening for colon cancer
Colonoscopy: How to Prepare
Your colon must be completely clean in order to ensure a thorough, safe colonoscopy. Your doctor may place you on a liquid diet for one to two days prior to your procedure. You may also need to take a laxative or undergo an enema. There are a number of different preparation options, which your doctor will discuss with you. You can learn more about the importance of good bowel prep by viewing this video.
Colonoscopy: What to Expect
On the day of the colonoscopy, you arrive at the endoscopy suite one or two hours before your procedure. Make sure an adult who can accompany you home is with you. When you arrive, you will register and give your medical history.
During the colonoscopy, your doctor will:
- Insert an intravenous line to administer fluids and sedatives.
- Perform a digital rectal exam, placing a gloved, lubricated finger inside your rectum.
- Place the colonoscope into the rectum, advancing it up the colon to the cecum. A video camera on the colonoscope transmits images of your colon to a nearby monitor.
- Inflate the colon with air to improve visibility.
- Biopsy or remove polyps to send to a laboratory for analysis. Your doctor can insert instruments through the colonoscope in order to remove tissue samples.
- Treat any bleeding in the colon.
After the procedure, you remain in recovery for one to two hours until the sedation wears off. Your doctor will discuss the results with you. Then you may go home.
You should limit your activity for the remainder of the day. You may feel bloated from the air in your colon; walking may help relieve that.