The Pros and Cons of Colonoscopies

Story at-a-glance

  • About 1 in every 350 colonoscopies do serious harm. The death rate is about 1 for every 1,000 procedures
  • About 80 percent of endoscopes are cleaned using Cidex (glutaraldehyde), which does NOT properly sterilize these tools, potentially allowing for the transfer of material that could easily infect you
  • Asking what solution is used to clean the scope is a key question that could save your life. Make sure it’s been sterilized with peracetic acid, to avoid potential transfer of infectious material from previous patients


This is an older article that may not reflect Dr. Mercola’s current view on this topic. Use our search engine to find Dr. Mercola’s latest position on any health topic.

By Dr. Mercola

Colon cancer is the second leading cause of cancer-related deaths in the United States. According to the Centers for Disease Control and Prevention (CDC),1 nearly 135,000 people were diagnosed with the disease in 2012, and more than 51,500 died from it.

Men and women over the age of 50 at average risk of colorectal cancer are typically recommended to get tested either by:2

  • Fecal occult blood testing (FOBT) on an annual basis, to check for signs of blood in your stool
  • Flexible sigmoidoscopy every five years
  • Colonoscopy every 10 years

Despite the fact that there are three acceptable screening methods, most doctors simply recommend colonoscopy, and researchers have found that in most instances, doctors completely fail to review all the options and the benefits and drawbacks of each with their patients.

In essence, most doctors simply choose for their patients, without going through the steps of informed consent, and most often they choose colonoscopy.

When Given Options, More People Go Through with Testing

Interestingly, recent research3 shows that when patients are allowed to choose the screening method, more people end up going through with the test. As reported by Reuters:4

“About 1,000 patients were divided into three groups and randomly assigned to get either FOBT or colonoscopy, or given a choice between the two options.

Over three years, 42 percent of participants given a choice between the tests followed through with screening and 38 percent of people assigned to get colonoscopies did so. Just 14 percent of the patients assigned to FOBT got the test done each year.”

Side Effects and Drawbacks of Colonoscopies You Need to Be Aware Of

As noted in the video above, narrated by Dr. Michael Greger, about 1 in every 350 colonoscopies end up doing serious harm. Death from colonoscopy, while rare, also does occur.

The death rate is about 1 for every 1,000 procedures,5 and with 15 million colonoscopies being done each year in the U.S., that means about 15,000 Americans die as a result of this routine procedure.

Sigmoidoscopies tend to have 10 times fewer complications, yet most doctors still recommend colonoscopy nearly 95 percent of the time.

Interestingly, other developed countries favor the FOBT stool test. Part of the reason for this is that in other countries doctors do not get paid for procedure referrals.

In the U.S. however, doctors typically do get financial kickbacks when referring patients for various procedures, and as noted by Dr. Greger, “it’s estimated that doctors make nearly a million more referrals every year than they would have if they there were not personally profiting.”

Unfortunately, most doctors also fail to inform their patients of the risks of colonoscopy, which include:6,7

  • Perforation of the colon (people at higher risk include those with diverticulitis, diseases of the colon, and adhesions from pelvic surgery)
  • Dysbiosis and other gut imbalances, caused by the process of flushing out your intestinal tract before the procedure with harsh laxatives8
  • Complications from the anesthesia. Many experts agree you should opt for the lightest level of sedation possible, or none at all, as full anesthesia increases risks
  • False positives. According the Prostate Cancer Foundation,9 an estimated 30 to 40 percent of men treated for prostate cancer have harmless tumors that would never have caused problems in their lifetime.
  • As noted by to Jessica Herzstein, a preventive-medicine consultant and member of the U.S. Preventive Services Task Force, “you’re going to die with them, not of them.”

    False positives lead to unnecessary treatments that are nearly always harmful, in addition to the anxiety a cancer diagnosis brings.

    For example, incontinence and erectile dysfunction are two common side effects of radiation therapy, and hormone therapy has been linked to osteoporosis and depression.

  • Infections caused by improperly disinfected scopes

If You Still Decide to Get Tested, BE CAREFUL, As 80 Percent of Instruments Are NOT Properly Sterilized

Click HERE to watch the full interview!

Download Interview Transcript

The primary tools used to screen for colon cancer are sigmoidoscopes and colonoscopes. These devices are not disposable, so they must be sterilized between each use. This, it turns out, poses a very significant problem that most patients are not aware of.

According to Lewis, a retired whistleblower microbiologist with the Environmental Protection Agency (EPA), about 80 percent of endoscopes are cleaned using Cidex (glutaraldehyde), which does NOT properly sterilize these tools, potentially allowing for the transfer of infectious material from one patient into another.

As Lewis explains in this recent interview (included above), flexible endoscopes have several basic components. One is a long, flexible tube with a tiny camera at the end, which allows the doctor to view the inside of your colon. There are also two internal channels in this tube, a biopsy channel and an air/water channel.

When the physician sees evidence of a tumor, he or she can insert a little claw through the endoscope, into the patient, and grab a piece of tissue and pull it back out through the biopsy channel. The air/water channel allows the doctor to clean the lens of the camera, which frequently gets covered with blood and other patient material.

The air/water channel is much smaller in diameter than the biopsy channel, and this is where the greatest risk of contamination originates, because while the biopsy channel is large enough to be scrubbed clean with a long brush, the air/water channel is too small to accommodate a brush.

About 80 percent of the time, flexible endoscopes are simply submerged in a 2 percent glutaraldehyde solution (Cidex) for 10 to 15 minutes to disinfect them between patients, and this simply isn’t sufficient to clean out the air/water channel that’s been contaminated with tissue, blood, and feces.

As a result, this material can get flushed out into subsequent patients. So, the problem, in a nutshell, is that doctors are re-using devices that are impossible to properly clean. So if, for whatever reason, you are compelled to get a colonoscopy or flexible sigmoidoscopy, then it is IMPERATIVE that you contact the office before the procedure to make sure they are decontaminating the scope properly with peracetic acid.

When Getting a Colonoscopy, Make Sure Peracetic Acid Was Used to Clean the Scope

Lewis launched a study with a university in which he looked at the internal channels, the air/water channel, and the biopsy channel, and collected samples of patient material from those channels. He then tested various ways of treating that layer of patient material to determine what was required to remove it from the inner channels.

As mentioned, submerging a flexible endoscope in a 2 percent glutaraldehyde solution (Cidex) for 10 to 15 minutes did not clean out the internal channels. In fact, Lewis demonstrated that you can submerge those devices for two hours and there’s still infectious material, such as HIV, trapped inside those internal channels.

What’s worse, not only does Cidex not sterilize the devices, it actually complicates the problem, because glutaraldehyde works like formaldehyde (it’s just a smaller molecule) — it preserves and embalms tissue, allowing the trapped material to build up over time.

There is a safer cleaning alternative however, and knowing this could very well save your life. About 20 percent of flexible endoscopes in the U.S. are cleaned with peracetic acid between patients rather than Cidex. Peracetic acid (which is similar to vinegar) is used in organic chemistry labs to dissolve proteins, and it does a FAR better job than glutaraldehyde.

The reason nearly 80 percent of clinics still use glutaraldehyde is because it’s cheaper. Even pennies per procedure add up when you’re doing them by the thousands each year, and hospitals are under pressure to save money wherever they can.

However, when your health and life is at stake, saving pennies becomes inconsequential, and you’d be wise to forgo any hospital that still uses Cidex to clean their endoscopes. How will you know how any given facility cleans their scopes? You have to ask. If you’re having a colonoscopy or any other procedure using a flexible endoscope done, be sure to ask:

  • How is the endoscope cleaned between patients?
  • Specifically, which cleaning agent is used?
  • How many of your colonoscopy patients have had to be hospitalized due to infections?

If the hospital or clinic uses peracetic acid, your likelihood of contracting an infection from a previous patient is very slim. If the answer is glutaraldehyde, or the brand name Cidex (which is what 80 percent of clinics use), cancel your appointment and go elsewhere. As for the third and last question, the answer you want is zero.10

Prepping for Your Colonoscopy

Getting a colonoscopy requires preparation to clean out your colon. Typically, this includes skipping dinner and breakfast before the procedure, and drinking 2 to 4 liters of a foul-tasting liquid containing laxatives and electrolytes. However, recent research suggests you may not have to go through the rigors of fasting — a step that dissuades many from getting a colonoscopy in the first place.

As reported by The Washington Post:11

“[T]he first glimmer of an alternative way of preparing for the procedure emerged ... at the Digestive Disease Week conference, where Levy presented the results of a study on 10 people that involved the same generally-used laxative and a carefully prepared diet of solid foods and liquids.

The patients, aged 46 to 73, were given measured portions of cereal, pasta salad, pudding, juices, chicken consomme, a vanilla smoothie, and a pina colada type drink spread across a normal lunch-dinner-breakfast eating schedule. Eight of the first 10 patients ate it all, and the other two consumed 95 percent of it. None reported bloating, nausea, vomiting, or cramping. When they examined the patients, doctors rated 9 of the 10 cleansings ‘good’ and 1 ‘excellent.’"

Peppermint Oil May Make a Colonoscopy Less Painful

Dr. Greger at NutritionFacts.org12 presents yet another alternative: peppermint, which helps relax the muscles and reduce spasms in your colon. The use of peppermint during colonoscopy was suggested over three decades ago, but was never implemented. As noted by Dr. Greger in the video above:

“[C]olon spasm can hinder the progress of the scope and cause the patient discomfort. So, they tried spraying some peppermint oil at the tip, and in every case, the spasm was relieved within 30 seconds. Thirty seconds is a long time though when you have this snaking inside of you; so, the next innovation would be to just use a hand pump to flood the whole colon with a peppermint oil solution before the colonoscopy.

[It’s a] simple, safe, and convenient alternative to injecting an anti-spasm drug, which can have an array of side effects ...”

Mixing peppermint oil into barium enemas has also been shown to be effective. Even taking a few peppermint oil capsules orally, four hours before the procedure, helped speed up the procedure by reducing spasms and pain.

Should You Have Routine Colonoscopies Starting at 50?

I’m 61 and I’ve never had a colonoscopy and have no plans of ever getting one. While I believe they can be valuable as a diagnostic tool, I feel confident that with my diet (which includes daily amounts of raw turmeric) and lifestyle it’s highly unlikely I would develop colon cancer. But for many people who are at higher risk, colonoscopies may be an effective strategy. Colon cancer grows very slowly, and it’s one of the top leading cancers that kill people, so early detection is important.

Certainly, you could opt for an annual guaiac stool detection test — which checks for hidden blood in your stool — but this test also produces many false positives, and the latest evidence suggests this test doesn’t work very well. Another alternative is to get tested by flexible sigmoidoscopy13 every five years. It’s similar to a colonoscopy, but uses a shorter and smaller scope, so it cannot see as far up into your colon.14

On the upside, it’s associated with fewer complications, although you still need to check with the hospital or clinic to make sure they’re using peracetic acid to clean the device.  Ultrasounds have also proven to be of value.

Overall, visual inspection is the most reliable way to check for colon cancer, and this is what the colonoscopy allows your doctor to do. If polyps are found in their early stages, your doctor can simply snip them off right then and there. So a colonoscopy is not only a diagnostic tool, it can also serve as a surgical intervention. They take a picture of the polyp, clip it, capture it, and send it to biopsy. So it could save your life, and it’s definitely something to consider.

However, you don’t want to risk complications or infections by having the procedure done with a contaminated piece of equipment! So please remember, asking what they use to clean the scope could save your life. Only agree to the procedure in a facility that uses peracetic acid as a cleaning solution.

This is a very simple strategy that will not only protect your health, but as more people get wise to this and start demanding the use of peracetic acid, we can improve the safety for all patients undergoing these procedures.


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