backup og meta
Health Screening
Ask Doctor

What is a Colonoscopy? Everything You Need to Know

Medically reviewed by Kristina Campos, MD · General Practitioner

Written by Sky Abundo · Updated Nov 09, 2021

What is a Colonoscopy? Everything You Need to Know

A colonoscopy is a medical procedure wherein a doctor uses a colonoscope to check inside your large intestines or colon.  This procedure is a test to check if there are any changes or problems within these areas.

The colonoscope is a long tube with a tiny camera at the tip. It is inserted into the rectum and allows doctors to observe the inside of the colon. The scope also allows doctors to cut off polyps and take tissue samples.

Colonoscopies were developed in the 1960s. They allowed doctors to be more thorough and certain in diagnosing issues having to do with the large intestine, by finding growths and cancers in the area.

When do you need a colonoscopy?

Your doctor or health care provider may recommend a colonoscopy to investigate the potential causes of various symptoms. It may also be performed as part of a check-up.

Here are some reasons why your doctor might recommend you to undergo a colonoscopy:

To look at intestinal changes or symptoms

If you are experiencing abdominal pain, rectal bleeding, chronic constipation, chronic diarrhea, and various intestinal problems, your doctor might use a colonoscopy as a way to investigate the causes.

Colon cancer screening

A colonoscopy is a great way to check for any signs for colon cancer. If you have no other risk factors or indicators pointing to colon cancer, your doctor might recommend you get regularly checked through a colonoscopy starting at 50 years old, regardless if you have family history or not. This can be done every 5 to 10 years.

Looking for polyps

Growths in the bowels can sometimes be found. These growths are called polyps. While mostly harmless, these polyps might become cancerous. These polyps can be found during a colonoscopy and removed to avoid further risks.

How does it work?

On the day of your colonoscopy, the medical staff on hand will brief you on the specifics of the procedure. They might offer you painkillers or sedation to calm your nerves.

The procedure itself will take around half an hour to 45 minutes. A thin, flexible tube with a camera attached to its end will be inserted in your rectum. To open up your bowels, air will be pumped into it. This tube will the, go around your large intestine, collecting data and cell samples along the way. If there are polyps found, doctors sometimes opt to remove them during the procedure.

How to prepare for a colonoscopy

Leading up to your colonoscopy, your doctor will require you to clean your colon. Any dirt or residue might complicate the check-up since it might obstruct the camera’s vision of your bowels. Here are steps to take to clean your colon:

Observe a prescribed diet before the exam

You won’t be able to eat solids before the day of your exam. Drinks are also limited to clear liquids. These include water, tea, or coffee without milk or cream, broth, or carbonated drinks. You should also stay away from red liquids as this can look like blood during the test. You should not drink or eat anything after midnight, the night before your procedure.

Sometimes patients are prescribed a low fiber diet. Usually, no food by mouth is usually done a few hours before a procedure depending on the case.


Your doctor may advise you to take a laxative the night before your check-up, as well as the morning of.

Enema kit

Your doctor might also recommend you use an over-the-counter enema kit in some cases. You may be advised to use this enema kit the night before or the morning of your procedure. However, this is not the main way to clean your colon as it only effectively cleans the lower parts of your colon.

Medication Adjustments

If you take medication for diabetes, heart problems, high blood pressure, or medication and supplements with iron, you need to inform your doctor a week before your exam. In general, you need to inform your doctor of any medication you are taking as this might influence the results of the procedure.

Risks and complications of colonoscopy

While generally a safe procedure, some complications and risks might still occur. Here are some issues that are associated with colonoscopy:

  • Bleeding
  • Perforation of the colon
  • Breathing or heart problems that might occur due to the sedative taken
  • Severe pain coming from your abdomen
  • While rare, death can also be a potential risk
  • Key takeaway

    A colonoscopy is a medical test that doctors use to check your colon or large intestine. Doctors insert a thin and long tube from your rectum through your large intestines. Colonoscopies are also a way for doctors to check for cancer as well as remove polyps that might lead to cancer.

    Learn more about Medical Procedures and Surgeries here.


    Hello Health Group does not provide medical advice, diagnosis or treatment.

    Medically reviewed by

    Kristina Campos, MD

    General Practitioner

    Written by Sky Abundo · Updated Nov 09, 2021

    ad iconadvertisement

    Was this article helpful?

    ad iconadvertisement
    ad iconadvertisement