Gastroscopy is a visual examination of the lining of the oesophagus, stomach and duodenum (first part of your intestine). A flexible tube (about the thickness of a ball point pen) is passed through your mouth and into the stomach. The tube will not interfere with your breathing. A small video camera, which can take photos, sends an image onto a video screen. The doctor can look for any abnormalities and if necessary biopsies (small tissue samples) can be painlessly taken for laboratory testing. Other procedures to treat specific conditions can be done through the endoscope.

These include:

  • Stretching (dilating) the narrowed areas of the oesophagus, stomach or duodenum.
  • Removing polyps and swallowed objects.
  • Treatment of bleeding vessels and ulcers by internal injection or diathermy.

You may be referred for a gastroscopy to investigate:

  • Indigestion, heartburn, reflux
  • Bleeding, anaemia
  • Nausea
  • Swallowing difficulties
  • Pain or abdominal discomfort


The stomach must be empty to obtain a clear view. You are asked not to eat for six hours before the test and drink three hours before the test. Prior to the procedure it is important for your doctor to know your medical history and in particular any previous endoscopies. Fully disclose any health problems you may have had as these may interfere with your gastroscopy, sedation or recovery. 

You should mention: 

  • An allergy or bad reaction to medicines or anaesthetics
  •  Taking medication to thin your blood including Warfarin, Dabigatran, Rivaroxaban, Aspirin or antiplatelet medication: e.g. Clopidogrel or Ticagrelor. Your doctor may ask you to stop taking these medications prior to your procedure or you may be given an alternative dose. 
  • Prolonged bleeding/clotting disorders or excessive bruising
  •  Diabetes – You must discuss this with your doctor or nurse before undertaking any period of fasting. 
  • Heart and lung problems including artificial heart valves and pacemakers. 
  • If you are pregnant or breast-feeding.


Serious complications are very rare. Perforation, a tear or bleeding from the oesophagus, stomach or duodenum may occur, especially after endoscopic therapies and may require admission to hospital, antibiotics and sometimes surgery.

 Bleeding can occur when the oesophagus has been dilated.

 There is a rare possibility that defects or disease may be missed. 

Reaction to the sedation is rare. 

If you would like further clarification of these rare complications, please discuss them with your specialist or nurse on admission. 

Please read these points carefully

  •  You should not drive a car, operate machinery or make any important decisions for 12 hours, as the sedation impairs your reflexes and judgement. Arrange for a friend or relative to take you home. 
  • You must contact your doctor if you suffer severe or prolonged pain or vomiting, passing of blood or high temperature. 
  • If you have any questions or concerns please raise these with your Doctor or Nurse before the procedure.

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