A colonoscopy is a routine procedure in which a highly trained doctor, called a gastroenterologist, inserts a colonoscope (a flexible tube with a camera at the tip) into the rectum and large intestine to carefully inspect the colon. The scope is about the width of your finger, and the procedure is typically painless because you’re sedated. A typical colonoscopy takes about 20 to 30 minutes.

The most common reason to have a colonoscopy is to screen for colon and rectal cancer. Colorectal cancer is the third leading cause of cancer deaths in the United States; the average risk for developing colorectal cancer is about six percent. Colonoscopy is a safe and effective means to detect colon cancer. Colonoscopy can also evaluate conditions such as bleeding, chronic diarrhea and anemia (low blood count).

Polyps are abnormal tissue growths that form on the colon lining. Polyps are almost always benign. While many benign polyps are harmless, others are considered “precancerous,” meaning they potentially could turn into cancer. Polyps generally grow slowly, so a small precancerous polyp may take 10 to 15 years to turn into cancer.

Approximately 30 percent of people over age 50 have precancerous polyps. Because almost all colorectal cancers start as small polyps, the early detection and removal of these polyps during a colonoscopy is an effective means to prevent colorectal cancer. The removal of polyps (polypectomy) is a painless procedure.

A colonoscopy is generally well-tolerated. You’ll receive a sedative and pain medication through an intravenous line placed by a nurse. Because of these medications, most people don’t experience pain or remember the procedure.

Prior to the procedure, a nurse will ask you questions to ensure that you understand the procedure and that you prepared your bowels properly. The gastroenterologist will also review the procedure with you. Your vital signs (blood pressure, heart rate and oxygen saturation) will be monitored closely before, during and after the procedure.

You will typically lie on your left side during the procedure, although in some cases you may be repositioned. During a colonoscopy, your doctor carefully inspects the colon and may remove polyps (polypectomy) or take biopsies (the painless removal of a small tissue sample).

Most colonoscopies last 20 to 30 minutes, followed by another 30 minutes in the recovery area.

Colonoscopy is a safe and routine procedure, but like any procedure it does carry some risks, which are small and uncommon. The most serious complication is a perforation, or a tear of the colon wall. In some cases, this might require emergency surgery. Bleeding is another possible complication, which can occur at the site where a polyp is removed or biopsied. Bleeding typically stops on its own but may require further treatments, including blood transfusions.

You’ll receive a sedative and a painkiller during the procedure. This type of sedation is called “moderate sedation,” sometimes described as “twilight sleep.” Most people are very comfortable, experience no pain and have no memory of the procedure. Technically, you’ll be “conscious” during the procedure and able to respond to questions. Some people may wake up towards the end of the procedure. You may even watch the procedure on a monitor.

If needed, sedatives can be increased. However, colonoscopy sedation is not “general anesthesia,” which is a deeper level of sedation. Any form of sedation does carry risks of breathing and heart problems, but these risks are very low with moderate sedation.

You’ll be monitored closely in the recovery area as the sedatives wear off. You may experience some cramping and bloating and you’ll be encouraged to pass gas which will help you feel better.

At the conclusion of your procedure, you’ll receive specific information about findings, post-procedure instructions and precautions.

Because sedatives may impair your judgment and coordination, someone else must drive you home and stay with you for at least two hours after the procedure.

There are generally no restrictions on what you can eat after a colonoscopy. Your doctor will give you specific instructions on whether you should take or avoid certain medications, depending on the colonoscopy findings. If your doctor took biopsies or removed polyps, you’ll be contacted separately with those results.

Colonoscopy is considered the gold standard for colon and rectum examination; however, polyps and other findings can sometimes go unseen. You can minimize this risk by taking your bowel preparation as instructed, to clean the colon as effectively as possible. On rare occasions, the scope cannot be advanced all the way around the colon. In cases like this, your doctor will discuss different alternatives with you.

Yes. National studies have demonstrated that the most effective way to cleanse the colon is to take the entire bowel preparation solution in two separate doses. This will help ensure that the colon will be optimally cleaned and minimize the need to reschedule your procedure.

To improve the taste of your preparation medication, try these tips:

• Add a citrus-flavored powdered drink packet.
• Chill the prep before drinking.
• Lick a lemon or lime wedge after drinks.
• Use a straw.

Yes. Bowel movements start very quickly after beginning the prep. Feelings of bloating, nausea, abdominal cramping or chills are common but should decrease over the course of the bowel preparation.

If you develop severe nausea or vomiting, stop drinking the bowel prep for 30 minutes, and then start again once you feel better.

No. Please take all of your medications as prescribed by your other doctors, unless specifically instructed otherwise.

The general rule is: if you can see through it, you can have it. You should stay well hydrated while drinking the prep, so please feel free to have as much of the clear liquid diet the night before as is tolerable to you.

Consider using petroleum jelly or diaper rash ointment around the anus before starting the prep and after each bowel movement to minimize irritation from bowel movements. You can use non-alcohol baby wipes or non-alcohol wet wipes for cleansing.

You must arrive at your given location one hour before your scheduled procedure time. Your entire stay will last two to three hours.

Medications commonly given during colonoscopy can temporarily impair judgment and coordination. Please rest for the remainder of the day for your health and safety. Some bloating, gas or mild cramping is normal and should diminish.

You should be back to normal the day after your procedure.

Because there is a small risk of bleeding for up to two weeks after a polyp is removed, please inform your doctor if you plan to travel by air after your procedure. We discourage booking an international flight within two weeks after your colonoscopy due to the small chance that a large polyp is removed and your doctor recommends cancelling the flight.