Get Screened Blog

What is a Colonoscopy? Doctors Share Everything You Need to Know


If you're nearing the age of 50 -- the age at which the American Cancer Society recommends regular colon cancer screening should begin -- you may be wondering: what is a colonoscopy?.

Whether it comes from your doctor's recommendations or through word-of-mouth from family and friends, information about colonoscopy can be confusing and perhaps a little intimidating.

Be Seen, Get Screened is here to debunk the myths and give you the facts about colonoscopy, straight from the doctors who perform these procedures.

What is it?

The Mayo Clinic describes colonoscopy as an exam used to detect changes or abnormalities in the large intestine (colon) and rectum, during which a long, flexible tube (colonoscope) is inserted into the rectum.

A tiny video camera at the tip of the tube allows the doctor to view the inside of the entire colon. If necessary, polyps or other types of abnormal tissue can be removed through the scope during a colonoscopy.1

Sometimes a mild sedative is given or anesthesia is administered to minimize any discomfort.

"The procedure is very low risk, performed under sedation, and is essentially painless." - gastroenterologist Timothy Ritter, M.D.

Why do I need it?

If you are age 50 or older, your doctor may recommend a colonoscopy in order to screen for colon cancer. Colon cancer is the most preventable cancer because precancerous polyps in the colon can be detected before the cancer develops.

"The No. 1 thing people can do to prevent colon cancer is to be compliant with screening colonoscopies and the removal of pre-cancerous polyps when found.” - colorectal surgeon Anna Toker, M.D.

These precancerous polyps develop slowly, leaving enough time for doctors to remove them before they grow and become cancerous. This is why screening colonoscopies are so important in the prevention of colon cancer, especially because the disease typically presents with no symptoms.

"Don't fool yourself into thinking that you probably don't need [a colonoscopy]. Colon cancer often has no symptoms. Colon polyps almost never have symptoms.” - gastroenterologist Jeff Bullock, M.D.

With screening and early detection, colon cancer can be much more treatable and preventable.

What can I expect?

Despite the measures physicians take to minimize discomfort during the procedure, many patients still have questions and concerns. If you do have questions or concerns about colonoscopy, your doctor should be able to help answer them.

“Once the topic of colon cancer screening comes up, many men cringe at the thought of having a colonoscopy. It takes time to educate them about the exam and explain to them that it is not as big of an issue as they imagine." - Curtis Chastain, M.D.

The day before the procedure, you will likely be asked to follow a special diet to help clean out your colon. You won't be able to eat solid food the day before the exam, and will be asked to use a laxative to help empty out your colon.2

A colonoscopy typically takes about 20 minutes to an hour. You'll begin the exam lying on your side on the exam table, usually with your knees drawn toward your chest.

The doctor will insert a colonoscope into your rectum, which contains a light and a tube that allows the doctor to pump air into your colon. The air inflates the colon, which provides a better view of the lining of the colon.

After the exam, it takes about an hour to begin to recover from the sedative. You'll need someone to take you home because it can take up to a day for the full effects to wear off. You shouldn't drive or go back to work for the rest of the day.

"I do these procedures all day, every day. Everyone wakes up in my recovery room relieved that it is over, and astonished at how easy it was. I reassure them that their experience will be the same.” - gastroenterologist Jeff Bullock, M.D.

How often should I have one?

One colonoscopy every ten years can prevent colon cancer, the number two cancer killer in men and women in the U.S. today.

"One colonoscopy doesn’t protect you for life. It can take between 5-10 years for a normal colon to develop a polyp and that polyp become cancer, so regular intervals of 5 years for high risk patients and 10 years for average risk patients are used to screen for cancer,” - colorectal surgeon Anna Toker, M.D.

Do I have other options for colon cancer screening?

Although colonoscopy is often considered the gold standard of colon cancer screening tests, there are different methods available that are recommended by the American Cancer Society.

While colonoscopy (and some other screening tests) require special preparation before the procedure, including medication and dietary adjustments, many tests do not. There are also screening tests that can be taken at home.

To learn more about these tests, view our comparative chart on colon cancer screening methods.

"Increasing use of all recommended colon cancer tests can save more lives and is cost-effective." - Tom Frieden, M.D.

Download our free Doctor Discussion Guide to start the conversation about colon cancer screening with your doctor.

Photo credit: MGDboston from

Get Colon Cancer eBook

Topics: Colon Cancer Information

1"Colonoscopy." Tests and Procedures. The Mayo Clinic, n.d. Web. 06 Nov. 2014.

2"Colonoscopy." Tests and Procedures: How You Prepare. The Mayo Clinic, n.d. Web. 07 Nov. 2014.