Gastroscopy enables the endoscopist to look inside the oesophagus, stomach and duodenum (first part of the small intestine). The procedure might be used to discover the reason for swallowing difficulties, nausea, vomiting, reflux, bleeding, indigestion, abdominal pain or chest pain.

The procedure involves the swallowing of a thin, flexible, lighted tube called an endoscope: before the procedure, the patient’s throat may be sprayed with a numbing agent to reduce the gag reflex, in addition, sedation may be given to help the tolerability of the procedure. The endoscope transmits an image of the inside of the oesophagus, stomach and duodenum to a screen, so the endoscopist can carefully examine the lining of these organs. The scope also blows air or sometimes CO2 into the stomach, which expands the folds of tissue and makes it easier for the endoscopist to examine the stomach.

The endoscopist can also insert instruments to treat abnormalities or remove samples of tissue (biopsies) laboratory examination.

Complications are rare; most people will probably have nothing more than a mild sore throat after the procedure. However, possible complications of gastroscopy include bleeding and damage to the lining of the gut.

The procedure takes about 10 minutes or less. If patients are sedated they will need to rest at the facility for one to two hours until the medication wears off.