to view an animated version of this procedure.
A colonoscopy is an exam of the large intestine, also known as the colon. The exam is done with a tool called a colonoscope. The colonoscope is a flexible tube with a tiny camera on the end. This tool allows the doctor to view the inside of your colon.
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A colonoscopy is used to examine, diagnose, and treat problems in your colon. The procedure is most often done to: Determine the cause of abdominal pain, rectal bleeding, or a change in bowel habits
Detect and treat
colon polypsTake tissue samples for evaluation under a microscope—biopsyStop intestinal bleeding
Monitor response to treatment if you have
inflammatory bowel disease
Complications are rare, but no procedure is completely free of risk. If you are planning to have a colonoscopy, your doctor will review a list of possible complications, which may include: BleedingPuncture of the bowel
Factors that may increase the risk of complications include: SmokingPre-existing heart or kidney conditionTreatment with certain medications, including aspirin and other drugs with blood-thinning properties
Prior abdominal surgery
, or other acute bowel disease
Previous treatment with
Be sure to discuss these risks with your doctor before the procedure.
Your doctor will likely do the following: Perform a physical examReview your health historyReview any medication you are takingTest your stool for blood
Talk to your doctor about your medications. You may be asked to stop taking some medications up to one week before the procedure.
On the day of the procedure: Wear comfortable clothing.Arrange for a ride home after the procedure.
Your colon must be completely clean before the procedure. Any stool left in the colon will block the view. This preparation may start several days before the procedure. Follow your doctor's instructions, which may include any of the following cleansing methods:
Enemas—fluid introduced into the rectum to stimulate a bowel movement
Laxatives—medications that cause you to have soft bowel movementsOral cathartic medications—a large container of fluid to drink that stimulates a bowel movement
For the entire day before your procedure: Do not eat any solid foods. This includes milk or cream in your coffee.Drink only clear liquids such as water, coffee without cream, ginger ale, apple juice, and sports drinks (do not drink red sports drinks)You can also have gelatin or popsicles as long as they are not redDo not drink alcoholIf you have diabetes, ask your doctor if you need to adjust your insulin dose
Your doctor may give you medication to help you relax.
You will lie on your left side. Your knees will be drawn up toward your chest. The colonoscope will be slowly inserted through the rectum. The colonoscope will inject air into the colon. The doctor will be able to see the lining of the colon with a small video camera on the colonoscope. The colonoscope will be gently passed through the colon to view the entire area.
A tissue sample or polyps may be removed during the procedure. This is done with small tools passed through the colonoscope.
Most people report some discomfort when the instrument is inserted. You may feel cramping, muscle spasms, or lower abdominal pain during the procedure. You may also feel the urge to move your bowels. Tell the doctor if you feel any severe pain.
After the procedure, gas pains and cramping are common. These pains should go away with the passing of gas.
If any tissue was removed: It will be sent to a lab to be examined. It may take 1-2 weeks for results. The doctor can usually give an initial report after the scope is removed. Other tests may be advised.A small amount of bleeding may occur during the first few days after the procedure.
Be sure to follow your doctor's
instructions when you return home.
After arriving home, contact your doctor if any of the following occur: Bleeding from your rectum—Notify your doctor if you pass a teaspoonful of blood or more.Black, tarry stoolsSevere abdominal painHard, swollen abdomenSigns of infection, including fever or chillsInability to pass gas or stoolCoughing, shortness of breath, chest pain, severe nausea or vomiting
If you think you have an emergency, call for emergency medical services right away.
National Institute of Diabetes and Digestive and Kidney Diseases website. Available at:
http://www.niddk.nih.gov/health-information/health-topics/diagnostic-tests/colonoscopy/Pages/diagnostic-test.aspx. Updated September 11, 2013. Accessed September 15, 2014.
Frequently asked questions about colonoscopy and Sigmoidoscopy. American Cancer Society website. Available at:
http://www.cancer.org/Healthy/FindCancerEarly/ExamandTestDescriptions/faq-colonoscopy-and-sigmoidoscopy. Accessed September 15, 2014.
Last reviewed September 2016 by Daus Mahnke, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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