A colonoscopy is a colon cancer screening procedure that allows your doctor to examine the lining of your large intestine, or colon. It’s a way to check for colon polyps, ulcers, tumors and other early signs of colon cancer or colorectal cancer. Colonoscopies are essential because they help your doctor find and treat colorectal cancers in their earliest stages. The earlier the condition is found, the better the prognosis. That makes a colonoscopy one of the most effective ways to test for colon cancer and protect your health and life.

What to Expect

Before Colonoscopy

Colonoscopy prep requires you to empty your colon completely. Starting about 12 hours before your exam, you’ll be required to avoid solid foods and colored liquids. You may also need to take a laxative and possibly perform an enema.

During Colonoscopy

On the day of your colonoscopy appointment, you’ll be given sedation medication through an IV so you feel relaxed while your doctor examines the entire length of your large intestine (colon).

During the colonoscopy, you’ll lie on your side on an examining table with your knees bent. Your doctor will insert a narrow scope (colonoscope) with a tiny camera on the end through your anus to examine your rectum and your large intestine. They will look for irregularities, such as colon polyps – fleshy growths in your colon’s lining that can lead to cancer. If any polyps are found, they can be removed via a colonic polypectomy using tools inserted through the tube. Your doctor can also collect tissue samples during the procedure. Any abnormal tissue can be biopsied to test for colorectal cancer.

During a virtual colonoscopy (CT colonography), your doctor will perform CT scans to produce pictures of your colon. You’ll lie on your back and your stomach so your doctor can get images from different angles. These scans are then reviewed to check for colon polyps and other abnormalities.

Both a colonoscopy and a virtual colonoscopy each take about 30 minutes to complete. Recovery time is usually about an hour.

After Colonoscopy

After a colonoscopy, it can take up to an hour for the sedative to begin to wear off, and up to a day for the effects of the sedative to disappear completely. Because of this, you won’t be able to drive or work after the colonoscopy, and will need to arrange for a ride home. You should be able to return to normal activity the following day.

Risk Factors

If you're 50 or older, your doctor will probably want you to have colonoscopies regularly – this is the most common colonoscopy age to begin getting screened.

If you're younger, and any of the following colon cancer risk factors apply, your doctor may suggest you start early colonoscopy screenings:

  • You have a close relative with colon polyps or colon cancer
  • You have a genetic syndrome like familial adenomatous polyposis (FAP) or hereditary non-polyposis colon cancer (Lynch syndrome)
  • You suffer from inflammatory bowel disease, Crohn's disease or ulcerative colitis

Ask your doctor when you should start and how often you should have a colonoscopy.

Colon cancer grows slowly and doesn't always cause symptoms in the early stages. But as it progresses, it can cause:

  • Abdominal cramps or frequent gas pains
  • A feeling that your bowel won't empty completely
  • Bloating
  • Blood in your stool (often bright or very dark) or rectal bleeding
  • Changes in bowel habits such as diarrhea or constipation
  • Fatigue
  • Unexplained weight loss

If you notice any of these warning signs, call your colonoscopy doctor (gastroenterologist).


Aurora Health Care operates colorectal cancer screening centers in Milwaukee, Sheboygan, Green Bay, and throughout eastern Wisconsin. Search for a clinic near you or find the nearest gastroenterologist and make your colonoscopy appointment today.

Find a Doctor

Use our tool to find the type of doctor who’s just your type.  

Classes & Events

We offer a wide variety of classes and community events.

Your Life Your Health

myAurora makes it easy to manage your care online, anytime.