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  • Endoscopy is a procedure where a thin flexible tube (endoscope) is used to view the lining of your stomach or bowel.  The image produced via the video processor is displayed on a television screen providing an excellent view for your specialist.  Special instruments can be passed down the endoscope to obtain a biopsy (a tiny sample of tissue) or to remove polyps.  All samples are sent to the laboratory for analysis.

  • Gastroscopy is an endoscopy of the oesophagus, stomach and duodenum.

  • Colonoscopy is an endoscopy of the large bowel (colon).


  • Most patients experience little discomfort during the procedure and, with sedation, recall very little about it.  Patients undergoing colonoscopy sometimes experience a feeling of wind pain or cramp as the endoscope goes round the corners in the bowel.  This discomfort is usually short-lived.  Any bloating afterwards settles as wind is passed.

  • A gastroscopy produces an unfamiliar sensation and can be uncomfortable but is not painful. Some patients experience a feeling of being bloated.


  • The endoscope is completely cleaned and disinfected between each patient to avoid transmission of infections such as hepatitis.  There is a very small risk of teeth being damaged during a gastroscopy procedure.

Serious complications of gastroscopy and colonoscopy are rare, at less than 1 in 10,000 examinations for gastroscopy and 1 in 3,000 for colonoscopy.  However unusual outcomes can occur and include the following:

  • Gastroscopy and colonoscopy are considered to be very accurate tests.  However there is a risk that a significant abnormality can escape detection.

  • Intolerance to the bowel preparation for colonoscopy.  Some people develop dizziness, headaches or vomiting.

  • Reaction to the sedatives.  This is very uncommon but can be of particular concern in people who have severe heart disease, lung or neurological disease.

  • Perforation (making a hole in the wall of the intestine) - this is a risk where large polyps are being removed from the bowel - approximately 1 in 1000 such procedures. 

  • Significant bleeding - again this tends to only occur following removal of polyps, is rare (1 in 500 polypectomies) and usually dealt with during the procedure - although late bleeds can occur up to one week following removal of polyps.

  • In the unlikely event that these complications occur you may require a blood transfusion or possibly surgery.

  • If you wish to have further details please discuss this with Dr Parkes before the procedure.

  • If you have any of the following symptoms in the hours or days after your colonoscopy you should contact Dr Parkes immediately:  severe abdominal pain, black tarry motions, persistent bleeding, fever, or any other symptoms that cause you concern.


  • You will be recovered in the day care department or back in your room.  Dr Parkes will then come and discuss the findings of your endoscopy prior to discharge. When you are ready to be discharged you will be walking and talking but may feel a bit "sluggish".  It may be sensible to go home and put your feet up for a few hours.  Do not have alcohol on the day of the procedure.

  • Following a gastroscopy you can consume normal diet and fluids after discharge.  If you have had a local anaesthetic throat spray you will need to be careful with the temperature of foods  and fluids for the first two hours as it will take this long for the throat spray to fully wear off.

  • Following colonoscopy it is important to drink plenty of fluids as the bowel preparation has a tendency to dehydrate the body.  You can resume a normal diet immediately following discharge.  

  • If a sedative has been administered you should not drive for 24 hours after the procedure.  Also do not operate machinery or make important decisions that day.  On the day after your procedure you may resume all normal activity.


You will be given details of any preparation by Dr Parkes or by the endoscopy department.  For colonoscopy the bowel MUST be completely clear for the examination to be accurate.  It is therefore very important that the instructions you are given are followed carefully.  

    Please bring with you:

    • A list of current medications you are taking.

    • Details of your medical insurance and authorisation code if applicable.​

    If you are given sedation for the procedure you will need someone to drive you home afterwards.  By law you are not permitted to drive yourself.

    What to do on arrival:

    • Further information regarding the procedure you are having will be made available to you.

    • A nurse will obtain health details from you.

    • You will be asked to change into one of our gowns.

    When to take normal medications:

    • Staff will advise patients on what medications should be stopped before the procedure.  Because biopsies are often taken, drugs that may promote bleeding (for example, warfarin, clopidogrel) may need to be stopped some days before the procedure.  Please check with staff. 

    • All normal medications can be taken four hours before starting preparation or four hours after finishing preparation to allow for absorption. 

    • Patients taking oral contraceptives need to be aware that efficacy cannot be guaranteed due to bowel preparation.


    Please contact either Prof Parkes' secretary by email at, the Nuffield Hospital on 01223 303336 or the Spire Cambridge Lea on 01223 266990 who will be pleased to answer your questions.

    FAQs: FAQ
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