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We offer Gastroscopy at both our Credit Valley Hospital and Mississauga Hospital locations.

Gastroscopy is a test where a doctor passes a thin, flexible tube called an endoscope through your mouth and into your esophagus, stomach and duodenum (which is the first portion of your small intestine). This procedure allows the doctor to:

  • examine the lining of the upper part of your gastrointestinal tract
  • take pictures of what is seen
  • use a small brush to collect cells for analysis

Gastroscopy can be used to diagnose:

  • persistent upper abdominal pain, nausea, vomiting or difficulty swallowing
  • the cause of bleeding from the upper gastrointestinal tract (your esophagus, stomach and duodenum)
  • inflammation, ulcers and tumors of the esophagus, stomach and duodenum

You might hear your doctor or other medical staff refer to Gastroscopy as upper GI endoscopy, esophagogastroduodenoscopy (EGD) or panendoscopy.


A referral from a doctor is required.

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Why is Gastroscopy Done?

In addition to diagnosing problems with your esophagus, stomach and duodenum (the first portion of the small intestine), your doctor might use Gastroscopy to obtain a biopsy (small tissue samples). A biopsy helps your doctor distinguish between benign (harmless) and malignant (cancerous) tissues.

Remember, biopsies are taken for many reasons, and your doctor might order one even if he or she does not suspect cancer. For example, your doctor might use a biopsy to test for Helicobacter pylori, the bacterium that causes ulcers.

Your doctor might also use Gastroscopy to perform a cytology test, where he or she will introduce a small brush to collect cells for analysis.

Gastroscopy is also used to treat conditions of the upper gastrointestinal tract. Your doctor can pass instruments through the endoscope to directly treat many abnormalities. This will cause you little or no discomfort. For example, your doctor might stretch (dilate) a narrowed area, remove polyps (usually harmless growths) or treat bleeding.

How to Prepare for Gastroscopy

You should have nothing to eat or drink, including water, after midnight the night before your test. Your doctor will tell you when to start fasting as the timing can vary.
Tell your doctor in advance about any medications you take; you might need to adjust your usual dose for the examination. Discuss any allergies to medications as well as any medical conditions you have, such as heart or lung disease.

Can I Take My Current Medications?

Most medications can be continued as usual, but some medications can interfere with the preparation or the examination. Inform your doctor about medications you’re taking, particularly aspirin products or antiplatelet agents, arthritis medications, anticoagulants (blood thinners such as warfarin or heparin), clopidogrel, insulin or iron products. Also, be sure to mention any allergies you have to medications.

What to Expect During Gastroscopy

Your doctor might start by spraying your throat with a local anesthetic to numb it, or by giving you a sedative to help you relax. You'll then lie on your side, and your doctor will pass the endoscope through your mouth and into your esophagus, stomach and duodenum. The endoscope does not interfere with your breathing. Most patients consider the test only slightly uncomfortable, and many patients fall asleep during the procedure.

What Happens After Gastroscopy?

You will be monitored until most of the effects of the medication have worn off. Your throat might be a little sore, and you might feel bloated because of the air introduced into your stomach during the test. You will be able to eat after you leave unless your doctor tells you not to.

Your doctor will explain the results of the test to you, although you'll probably have to wait for the results of any biopsies performed.

If you have been given sedatives during the procedure, someone must drive you home and stay with you. Even if you feel alert after the procedure, your judgment and reflexes could be impaired for the rest of the day.

Are There Any Possible Complications?

Although complications can occur, they are rare. Bleeding can occur at a biopsy site or where a polyp was removed, but it's usually minimal and rarely requires follow-up. Perforation (a hole or tear in the gastrointestinal tract lining) may require surgery but this is a very uncommon complication. Some patients might have a reaction to the sedatives or complications caused by heart or lung disease.

Although complications after Gastroscopy are very uncommon, it's important to recognize early signs of possible complications. Contact your doctor immediately if:

  • you have a fever after the test
  • you notice trouble swallowing
  • you have increasing throat, chest or abdominal pain
  • you experience bleeding, including black stools. Note that bleeding can occur several days after the procedure.
If you have any concerns about a possible complication, it is always best to contact your doctor right away.​