This information was developed by the Publications Committee of the American Society for Gastrointestinal Endoscopy (ASGE). For more information about ASGE, visit

This information is intended only to provide general guidance. It does not provide definitive medical advice. It is important that you consult your doctor about your specific condition.

What is the purpose of a colonoscopy?

A colonoscopy is a minimally invasive procedure to screen for colorectal cancer and remove growths (polyps) before they turn into cancer, as well as to evaluate inflammatory bowel disease and other bowel-related conditions.  The procedure is performed with a colonoscope, a long, flexible tube the width of your index finger with a light and tiny camera at the end.

According to current guidelines, a screening colonoscopy is recommended for individuals over the age of 45, or those at risk due to family medical history, personal medical conditions, and lifestyle factors.

How is a colonoscopy performed?

  • An intravenous line will be placed in your arm, through which the anesthesiologist will administer gentle sedation, allowing you to sleep the entire time and have no discomfort.
  • You will lay on your left side while the gastroenterologist inserts the colonoscope through your anus to examine your large intestine while viewing a video monitor and capturing images.
  • If polyps or abnormal tissue are found, they may be removed or biopsied during the procedure.
  • Most procedures take 30 to 45 minutes.

What preparation is required before a colonoscopy?

Your doctor will give you dietary and “prep” instructions to follow closely before your colonoscopy.  This preparation ensures your bowels can be easily viewed during the procedure.

What happens following my colonoscopy?

  • You’ll spend 20-30 minutes in a recovery area while the sedation wears off, and you can eat immediately.
  • The gastroenterologist will speak with you before you go home.
  • If any biopsies were taken, those will come back in a few days.
  • Because of the anesthesia, you will need someone to escort you home. You should plan to take it easy the rest of the day, and you cannot drive a car following the procedure until the next day.

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