I’ve heard that it is possible to do a colonoscopy without anesthesia. Can you comment on the tradeoffs for this decision?
—Apple Bow
I recently had my first colonoscopy — I am making some progress on getting up to date with my health maintenance. The option of not being sedated was not offered to me. Though, to be fair, I didn’t ask about the possibility.
In the interest of being transparent, I am neither a gastroenterologist nor an anesthesiologist. The only unsedated colonoscopy I witnessed was when Katie Couric had one live on the Today show over two decades ago to promote colon cancer screening.

The most obvious downside to having a colonoscopy without sedation is that it may be painful. There are a handful of studies looking at how well patients tolerate colonoscopy without sedation (see here and here). In both of these studies, a small number of patients did not tolerate an unsedated colonoscopy. About half of patients had no pain or mild pain, 25% to 30% had moderate pain, and some patients in both studies had severe pain.
The authors did not look at patient characteristics that might make pain during an unsedated colonoscopy more likely, but it is possible that colonoscopies that are more technically difficult might also cause more pain. For example, if you have had abdominal surgery in the past, you may have scar tissue around the intestines that could make a colonoscopy more difficult and more painful.
The goal of a screening colonoscopy is not just to identify colon cancer but also to identify polyps that could become colon cancer in the future. You should also consider whether an unsedated colonoscopy is as effective at doing so as a colonoscopy under sedation.
A recently published study looked at exactly this. The authors used registry data to compare how likely physicians were to identify different types of polyps during sedated and unsedated colonoscopies. They found that sedated colonoscopies were slightly more likely to identify the kind of polyps that are most likely to become cancerous. I can imagine that the physician being cautious not to cause pain might be less likely to spot some polyps because of how they would need to maneuver the colonoscope.
The downside of sedation is that it is responsible for most of the complications that occur during colonoscopy. But how likely are anesthesia-related complications? Most sedated colonoscopies today are done using a medication called propofol. A meta-analysis of propofol sedation for colonoscopy found that the risk of any complication with propofol was about 14%. But these complications were largely minor and included nausea, vomiting, dizziness, headache, and somnolence or drowsiness (though I am not quite sure why somnolence is considered a complication in this case, given that it is the desired effect). More dangerous complications, such as low blood pressure and low levels of oxygen in the blood, were quite rare.
Ultimately, the data suggest that unsedated colonoscopy is safe and well-tolerated by most patients who opt for it, though there may be a small risk of missing polyps that may become cancerous. Propofol sedation is safe and most complications are minor. If you are interested in pursuing a screening colonoscopy without sedation, you should discuss this with your gastroenterologist.
Community Guidelines
Log in
Anesthesiologist here. Everyone who undergoes a procedure with anesthesia (sedation/general anesthesia etc) is evaluated by the anesthesiologist first. A full medical history, surgical history and anesthetic history is taken. This helps determine your individual risk of complications. Anesthetics are individualized, a patient who may be at higher risk of complications may be offered a different anesthetic than someone with no risk factors. For a colonoscopy this could mean anything from no anesthesia, mild sedation (like a medication for anxiety and/or a pain medication), to deeper sedation with propofol where the patient is not conscious for the procedure. General anesthesia with a breathing tube is sometimes used in certain cases where that may be safer. The take away is that this is a question to discuss with your gastroenterologist and most importantly, your anesthesiologist.
I think it’s important to distinguish between general anesthesia, sedation, and no drugs (which used to be the standard). Unfortunately most providers only offer GA. I really can’t think of a reason to do that vs sedation, which makes you sleepy and comfortable, or maybe actually asleep during the procedure.
I don’t think that most providers only offer general anesthesia. Most offer IV sedation, and would only use general anesthesia if necessary in an individual case.
Hi. Thank you for this article. When you say “More dangerous complications, such as low blood pressure and low levels of oxygen in the blood, were quite rare.” What is rare in your perspective? What percentage had these serious complications?