The colon must be cleaned out. Any stool left in the colon will block the view. This process may start several days before the procedure. The doctor will give specific instructions. Bowel movements may be encouraged with 1 of these steps:
Enemas—fluid is passed into the rectum
Laxatives—medicine taken by mouth or placed into rectum
Oral cathartic medicine—a fluid that you drink
In the day before the procedure:
Solid foods will need to be avoided. This includes milk or cream in coffee.
Only clear liquids are allowed. This includes water, coffee without cream, ginger ale, apple juice, and sports drinks. Avoid red sports drinks.
Gelatin or popsicles are allowed as long as they are not red.
Alcohol needs to be avoided.
Insulin medicine may need to be changed.
Comfortable clothes should be worn on the day of the colonoscopy. A ride home will be needed.
Medicine may be given to help you relax. You'll probably feel sleepy.
Description of the Procedure
You will lie on your left side. Your knees will be drawn up toward your chest. The scope will be slowly inserted into the rectum. It will inject air into the colon to help open the area. The doctor will slowly pass the scope up into the colon. The camera on the scope will send images to a monitor on the room. The doctor will be able to see the walls of the colon as the scope moves through.
Other tools can be passed through the scope. The tools may remove a sample of tissue or polyps. The tissue can then be sent for testing. The scope will be removed once the doctor is done.
How Long Will It Take?
Less than 1 hour
Will It Hurt?
There may be some discomfort when the scope is inserted. Some cramping or lower belly pain can happen during the procedure. Medicine will help to ease discomfort. Some will sleep through the procedure.
Gas pains and cramping are common after. These pains should go away with the passing of gas.
You will remain at the care center until you are able to leave. It may be 1 to 2 hours. It is best to take it easy for the rest of the day. Most can return to normal activity within 24 hours.
It may take 1 to 2 weeks to get results back from tissue sample. Other tests may be needed.
Call Your Doctor
Let your doctor know if recovery is not going as expected or you have any of the following:
Bleeding from your rectum—more than your doctor said you may see
Black, tarry stools
Severe belly pain
Hard, swollen belly
Signs of infection, including fever or chills
Problems passing gas or stool
Coughing, shortness of breath, chest pain, severe nausea or vomiting
If you think you have an emergency, call for emergency medical services right away.
Colonoscopy. National Institute of Diabetes and Digestive and Kidney Diseases website. Available at: https://www.niddk.nih.gov/health-information/diagnostic-tests/colonoscopy. Updated July 2017. Accessed January 10, 2020.
National Cancer Institute. Colon cancer treatment (PDQ®)-patient version website. https://www.cancer.gov/types/colorectal/patient/colon-treatment-pdq#link/_93 NIH external link. Updated January 31, 2020. Accessed January 10, 2020.
Last reviewed September 2019 by
EBSCO Medical Review Board
Daus Mahnke, MD
Last Updated: 10/16/2020
EBSCO Information Services is fully accredited by URAC. URAC is an independent, nonprofit health care accrediting organization dedicated to promoting health care quality through accreditation, certification and commendation.
This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.
To send comments or feedback to our Editorial Team regarding the content please email us at email@example.com. Our Health Library Support team will respond to your email request within 2 business days.