Colonoscopy: Expert insight on the procedure

Written by: Dr Amit Gera
Published: | Updated: 26/09/2023
Edited by: Sophie Kennedy

In this informative guide, revered consultant gastroenterologist Dr Amit Gera sheds light on how to prepare for a colonoscopy and reveals why the procedure is commonly performed. The leading specialist also discusses the associated risks and the recovery period following a colonoscopy.



What is a colonoscopy?


A colonoscopy is an exam used to look for changes in the large intestine (colon) and rectum, such as swelling, irritated tissues, polyps or cancer. During a colonoscopy, a long, flexible tube (colonoscope) is inserted into the rectum. The test can help find the cause of any bowel symptoms.


Why might a colonoscopy be performed?


A colonoscopy is performed to detect changes or abnormalities in the large intestine (colon) and rectum. It can be used to screen for colon cancer and other conditions, such as inflammatory bowel disease and polyps.


How should I prepare for a colonoscopy?


Preparation for a colonoscopy usually includes following a liquid diet for one to two days before the test. You will also need to take a laxative, have an enema or perhaps both to completely empty the colon. The day before your colonoscopy you’ll need to drink sachets of laxatives to empty your bowels ready for the test. You’ll also need to switch to a soft food diet at least forty-eight hours before the colonoscopy which may make your preparation easier.


What are the risks associated with colonoscopy procedures?


Complications of a colonoscopy are rare but can include perforated intestine, bleeding from the site where a tissue sample (biopsy) was taken or a polyp or other abnormal tissue was removed, and a tear in the colon or rectum wall (perforation). Fortunately, the risk of these complications is very low.


Are all patients suitable for a colonoscopy?


Not all patients can have a colonoscopy. Your doctor may advise against a colonoscopy if you have certain medical conditions, such as severe diverticulitis, ulcerative colitis or Crohn’s disease, or if you have had surgery on your colon. In some cases, your doctor may recommend an alternative screening test.


What is the recovery period like following a colonoscopy?


After a colonoscopy, you’ll need to rest for about an hour or until the effects of the sedative have worn off. You may feel bloated or pass gas for a few hours after the procedure, as you clear the air from your colon. You may also notice a small amount of blood with your first bowel movement after the exam but this is normal and will clear up.




If you wish to schedule a consultation with Dr Gera, you can do so by visiting his Top Doctors profile.

By Dr Amit Gera

Dr Amit Gera is a leading gastroenterologist in London who specialises in liver disease, irritable bowel syndrome, inflammatory bowel disease, acid reflux and colonoscopy.

Dr Gera qualified with distinction from Guy’s, King’s and St Thomas’ School of medicine in 2000. Between 2003 until 2011, he undertook his specialist training in gastroenterology in London and South East Thames. Dr Gera undertook a research fellowship at the Liver Unit in King’s College Hospital and gained advanced training in liver disease, viral hepatitis, transplantation and critical care. He has accreditation in gastroenterology, hepatology and general medicine.  

Dr Gera has been the Training Programme Director for the prestigious South Thames Gastroenterology training scheme and has run the regional gastroenterology teaching programme. He is the Lead Clinician for Upper GI Cancer and runs the viral hepatitis service for Queen Elizabeth Hospital, Lewisham and Greenwich NHS Trust.

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