What happens during a gastroscopy?

A gastroscopy (examination of the stomach) can help confirm or rule out the presence of medical conditions like gastritis or peptic ulcers. In this procedure, a flexible, thin tube (called a gastroscope) is used to look at the inside of the food pipe, the stomach, and part of the duodenum (the first part of the intestine). At the end of the gastroscope, there's a small camera with a lamp on it. The images from this video camera are sent directly to a screen.

Gastroscopy may be done if you have the following:

  • Chronic or recurring heartburn, nausea or vomiting
  • Nausea over a long period of time
  • Stomach pain
  • Trouble swallowing
  • Black-colored stool, which may be a sign of bleeding in the upper part of the digestive tract
  • Weight loss for no apparent reason
  • Suspected peptic
  • Suspected cancer of the food pipe or stomach
  • A check-up after stomach surgery

What needs to be done to prepare?

Before a gastroscopy, your doctor will tell you about the procedure, what it involves, and any associated risks. This includes information about mild sedatives or anesthetics you can be given to make the examination more comfortable. If you regularly use anticoagulants, you may need to stop taking them a few days before the gastroscopy. Your doctor will tell you how many hours before the gastroscopy you should stop eating or drinking. And after the examination you need to wait until the numbness in the back of your throat goes away.

The gastroscopy can only be done if you have signed a consent form first.

If you are given a sedative for the gastroscopy, you won't be allowed to drive a car or operate machinery for 12 to 24 hours afterwards. How long you need to wait depends on what type of sedative is used. Ideally, you should be picked up by someone or take a taxi home after the procedure. Some doctors recommend that someone comes to pick you up and take you home afterwards.

What happens during the examination?

Shortly before the gastroscopy, your mouth and throat will be numbed using a spray. Any removable dentures need to be taken out before the procedure. In Germany, the sedatives most commonly used for this purpose are called propofol and midazolam. They are injected into a vein and make you sleep for a short while.

A gastroscopy generally lasts about 5 to 10 minutes. This is what happens during it:

  • You will usually lie on your left side.
  • A tube or a protective ring is put between your teeth so your mouth stays open and you don't bite the gastroscope.
  • First you have to swallow so the gastroscope can enter your food pipe.
  • Then it is slowly pushed into your stomach and down to the entrance of your small intestine (the duodenum).

Using the images provided by the camera on the gastroscope, your doctor can look for redness or inflammations in your food pipe and on the lining of your stomach and duodenum. Things like bleeding, varicose veins, unusually narrow passages and stomach ulcers can be seen on the screen too.

It is also possible to take tissue samples using small pincers that are inserted through the gastroscope tube. This is not painful. The gastroscope can be used to suck out air and fluids as well. Bleeding, unusually narrow passages, and certain medical conditions can be treated directly during the procedure.

What are the possible risks or complications of a gastroscopy?

You may have a hoarse voice or a numb feeling in your mouth after a gastroscopy, caused by the anesthetic spray. You might also feel full and have to burp for a short while if more air was pumped into your stomach to see more in the images. Complications like bleeding and injury to organs caused by the gastroscope are very rare. This is also true regarding complications caused by sedatives, such as breathing problems or cardiovascular problems.

Although sedatives only cause you to sleep for a short while, you may still have trouble concentrating and feel tired for several hours afterwards.

Ben-Menachem T, Decker GA, Early DS et al. Adverse events of upper GI endoscopy (ASGE Practice Guideline). Gastrointest Endosc 2012; 76(4): 707-718.

Early DS, Ben-Menachem T, Decker GA et al. Appropriate use of GI endoscopy (ASGE Practice Guideline). Gastrointest Endosc 2012; 75(6): 1127-1131.

Messmann H. Klinische Gastroenterologie. Stuttgart: Thieme; 2020.

IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. informedhealth.org can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

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What happens during a gastroscopy?

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Updated on November 25, 2021

Next planned update: 2025

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Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

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