• Colorectal Cancer Info MAIN MENU
  • Screen MAIN MENU
  • Care MAIN MENU
  • Cure MAIN MENU
  • Get Involved MAIN MENU
  • Our Mission MAIN MENU

Subscribe to the Newsletter

A colonoscopy is one of the many tools in a doctor’s arsenal of screening for colon and rectal cancer (CRC). While the odds of developing colorectal cancer remain high, colonoscopies are a proven, effective, and safe way to screen, prevent, and catch colorectal cancer early, and they give you the best odds for a long, healthy, and productive life. 

During a colonoscopy, a doctor uses a thin, flexible tube equipped with a tiny video camera at the tip to look inside your colon and rectum. The doctor will search for anything abnormal and remove polyps, which are growths that can turn into cancer. Most colonoscopies are done with the patient under sedation (a sleep-like state). A colonoscopy should be completed at least every ten years but could be more often depending on the patient.

On average, one in 23 men will develop colorectal cancer at some point in their lifetime, while women have a one in 25 chance. 

Colonoscopies can help reduce colorectal cancer occurrence by 40% and mortality by about 60%, according to the American Cancer Society. Due to this significant impact, the number of colonoscopies performed each year has climbed steadily with more than 19 million performed in 2017 alone.

While there are risks associated with even the most routine medical procedures, the benefits of a colonoscopy significantly outweigh the associated risks for people ages 45 to 75. The American Society for Gastrointestinal Endoscopy estimates that only three in 1,000 colonoscopies leads to serious complications. But even when serious complications arise, it is exceedingly rare that they are life-threatening, and doctors are well-trained to treat any complications with proven methods.

Risks and Serious Complications

A 2010 study found that only 19 of more than 284,000 procedures resulted in death from a colonoscopy-specific complication (0.0066% of procedures). To put that into perspective, you have nearly an identical chance of dying as a result of colonoscopy as you do of being struck by lightning (0.0065%). 

While colonoscopy complications that lead to death are exceptionally rare, there are more common complications that may result in temporary discomfort or require further medical care. Some of these include:

  • Bleeding: If a tissue sample is taken, you may notice some bleeding from your rectum for a day or two after the procedure. This is typically not a reason for a concern. If bleeding persists for more than two days, let your doctor know.

  • Infection: Bacterial infections have been known to occur after a colonoscopy. They can can be safely treated by your doctor with medication.

  • Reaction to anesthesia: While all medical procedures requiring anesthesia carry some risk, cardiopulmonary complications are possible during colonoscopies. Be sure to talk to your doctor about the best types of anesthesia for your procedure.

  • Post-Polypectomy Electrocoagulation Syndrome: While extremely rare, this is a complication that involves an injury to the bowel. It can cause abdominal pain and fever. In the unlikely event it occurs, it can most often be treated with bed rest and medication. 

Risk for Complications Increase in Older Patients

Patients over the age of 75 are at higher risk for complications from colonoscopies due to the greater potential for underlying health issues. The prep for the procedure may also be more difficult for older patients. It can lead to dehydration or an electrolyte imbalance. Because of this, patients should ensure they have a clear plan for both prep and recovery. Before scheduling a colonoscopy, it is very important that older patients discuss all the benefits and risks of the procedure with their doctor. 


The data make it clear that doctor-ordered colonoscopies are significantly less dangerous to your long-term health than delaying or skipping the procedure. The risk of a potential colorectal cancer going undetected is significant. While your chance of dying from a colonoscopy is virtually the same as getting struck by lightning, colorectal cancer is unfortunately the second-leading cause of cancer-related deaths in America. 

Not sure if a colonoscopy is right for you? Get a free, personalized screening recommendation based on your risks. Click here to take our short survey


Don't miss another update.
Subscribe to our newsletter.




Related reading

Are you sure?

Clicking "Start Over" will empty your resources drawer and take you back to the beginning of the journey customizer. Would you like to continue?

Are you sure?

Clicking "Exit" will permanently close your resource drawer for the rest of the session. If you would like to minimize the drawer and access it from other pages, click the symbol next to "MY RESOURCES". Would you like to permanently exit the drawer?