Gastroscopy - Risks of a gastroscopy

A gastroscopy is a very safe procedure and the risks of serious complications are small.

If it's used to diagnose a condition, it has less than a 1 in 1,000 chance of causing a serious complication.

A gastroscopy used to treat a condition is more invasive and has a higher risk of complications. However, the risk is still relatively small, at around 1 in 100.

Some of the possible complications of a gastroscopy include:

  • adverse effects from sedation
  • bleeding
  • perforation (tearing)

These are described below.


Sedation is usually safe, but it can occasionally cause problems, such as:

  • feeling or being sick
  • a burning sensation at the site of the injection
  • small particles of food falling into the lungs and triggering an infection (aspiration pneumonia)
  • an irregular heartbeat
  • breathing difficulties

Very rarely, complications from sedation can result in a stroke or heart attack.


Sometimes, during a gastroscopy, the endoscope can accidentally damage a blood vessel, causing it to bleed. However, significant bleeding is very rare.

Signs of bleeding can include vomiting blood and passing black or "tar-like" stools.

The site of the bleeding can usually be repaired during a further gastroscopy. A blood transfusion may also be required to replace lost blood.


During a gastroscopy, there's a very small risk of the endoscope tearing the lining of your oesophagus, stomach or the first section of your small intestine (duodenum). This is known as perforation.

Signs of perforation can include:

  • neck, chest or stomach pain
  • pain when swallowing
  • a high temperature (fever) of 38C (100.4F) or above
  • breathing difficulties

If the perforation isn't severe, it can usually be left to heal by itself. You may be given antibiotics to prevent an infection occurring at the site of the tear. Surgery may be needed to repair more serous perforations.

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