A person may feel mild discomfort in the rectum or stomach area after a colonoscopy. However, people usually receive sedation or general anesthesia before a colonoscopy, so they will likely feel no pain.

The United States Preventive Services Task Force recommends colon cancer screenings, including colonoscopy, beginning at age 45 years. People who are at high risk may wish to start screening earlier than this.

This article takes a closer look at the colonoscopy procedure, how it may be painful or uncomfortable, and options for pain prevention.

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Fear of pain and embarrassment before a colonoscopy is common, and it may even deter people from seeking this potentially life-saving screening test.

Most colonoscopies in the U.S. happen when a person is sedated or under general anesthesia. In both scenarios, a person will feel no pain during the procedure. This is the case even when a person chooses to be awake during a colonoscopy.

A 2018 study involving 22,725 people who returned colonoscopy questionnaires reports that most did not mention experiencing pain.

A colonoscopy is a procedure to look for cancerous growths and polyps in the colon, which is the longest portion of the large intestine.

Before the procedure, a person lies on a table, usually in a hospital gown that is open at the back. An anesthesiologist or anesthetist inserts a needle into a vein in the hand or arm and injects medication to help relax the person and prevent pain. If a person receives a general anesthetic, this medication will put them completely to sleep.

During the procedure, a doctor inserts a long, flexible tube called a colonoscope in through the anus and rectum to access the colon.

There is a camera at the end of the tube to help the doctor see the colon. The doctor also inserts air into the colon to expand it and make it easier to see any unusual growths.

The procedure usually takes 30–60 minutes. If a doctor sees polyps or other growths in the colon, they may remove them and send them to a laboratory for further testing. This means that a colonoscopy can both test for and sometimes treat harmful growths in the colon.

In most cases, a person needs to prepare for the procedure a day or two in advance by taking laxatives and changing their diet to clean out the intestines. This ensures that a doctor can easily see the inside of the intestines.

People undergoing a colonoscopy are typically not fully conscious. A doctor may offer sedation, which means that a person is awake but unaware and feels no pain.

In other cases, a doctor may also recommend general anesthesia, which means that a person is totally unconscious and will have no memory of the procedure.

However, the following aspects of the procedure may be uncomfortable or even painful, with or without sedation:

  • Bowel preparation: There must be no stool in the bowel during the procedure. This means that a person usually needs to take laxatives for a day or two beforehand. This can cause diarrhea that may be painful. In some cases, a person may need to give themselves an enema, which can be uncomfortable but not usually painful.
  • Embarrassment and discomfort: A colonoscopy involves inserting a tube into the rectum. This can feel unnatural, scary, or embarrassing.
  • Pain during the procedure: A 2016 paper suggests that it is possible to comfortably perform a colonoscopy without sedation. However, the tube may irritate the colon or rectum, causing pain. In a 2018 study, 64.5% of 35,216 people who underwent a colonoscopy responded to a questionnaire, and, of that figure, 14.2% of people who did not have sedation said that they felt pain.
  • Pain after the procedure: Some people have stomach pain after a colonoscopy. A person may also experience mild irritation to their rectum, gas, or other digestive problems. These symptoms are usually mild and tend to go away in a few days. However, severe pain could signal a problem, such as damage to the colon or an infection.

It is normal to experience some stomach pain after the procedure, usually because the air causes gas. This sensation may be mild or intense, but it typically only lasts an hour or two. Some people experience mild stomach pain for a day or two after the procedure.

A person may also have temporary changes in digestion, such as constipation or diarrhea. If the tube irritates the rectum, anus, or intestines, there may be some discomfort when having a bowel movement.

Very rarely, a person may experience severe pain or bleeding that signals a serious complication, such as damage to the colon or an infection. A 2016 systematic review found four to eight serious complications per 100,000 procedures.

A person should contact a doctor right away if they experience:

Sedation is the standard of care for colonoscopies in the U.S. However, some doctors perform the procedure without sedation at a patient’s request or because of the potential risks associated with sedation.

Sedation adds another variable to the procedure and requires someone to monitor the patient for complications. This increases the resources needed for colonoscopy procedures and the risk of complications. However, the overall risk of complications remains very low.

For people who wish to avoid sedation, the following techniques may help ease or even prevent pain:

  • Relaxation: Fear can increase pain. Also, for many people, a colonoscopy is more embarrassing than painful, so relaxation may help with this.
  • Acupuncture: Some studies suggest that acupuncture may help a person relax and reduce their pain. The data are not conclusive, however, and other studies undermine claims about the effectiveness of acupuncture.
  • Music or audio therapy: Music and other forms of audio therapy, such as listening to a podcast, may help ease anxiety and distract a person during a colonoscopy.
  • Changes in technique: Using water rather than air to inflate the colon may reduce pain. Some evidence also suggests that using peppermint may reduce colon spasms. Additionally, smaller tubes and a very skilled endoscopist may also help reduce pain.

People who are planning to undergo a colonoscopy should discuss their options with a doctor. It is important to talk about fears and treatment goals. For example, some people fear the effects of anesthesia or complications from the procedure, while others do not want to feel anything or worry that the procedure will be embarrassing.

Knowing someone’s concerns can help a doctor identify the best way to perform the procedure.

It is important for a person to contact a doctor if they experience severe pain or any of the following after the procedure:

  • bloody bowel movements
  • bleeding from the anus
  • fever
  • confusion
  • dizziness
  • weakness

A colonoscopy can be frightening, especially for the first time. However, it remains a very effective way to detect and sometimes treat colon health problems, such as polyps and cancer. The procedure is quick, and it can be painless with sedation. It is much more comfortable than having advanced colon cancer.

People who feel anxious about having a colonoscopy can talk with a doctor and educate themselves about the procedure. Learning how a doctor performs it may help ease any concerns about pain and embarrassment.