What Is an Endoscopy and What Does It Show?

Your appointment letter says "upper endoscopy" — sometimes called a gastroscopy — and, understandably, the part most people want to know is what the day actually feels like. So let's walk through it in order. The short animated video at the top of this page, just under two minutes long, explains an upper gastrointestinal endoscopy in pictures: it shows how a doctor uses the test to view the lining of the upper part of your digestive system. The guide below follows the same journey, step by step.

Before you arrive

An endoscopy uses a thin, flexible tube with a small camera and light at its tip. For an upper endoscopy, that tube is passed gently through your mouth, so the stomach needs to be empty for the camera to get a clear view. Your unit will give you its own instructions about when to stop eating and drinking and whether to adjust any regular medicines, so follow that letter rather than general advice. Plan, too, for the trip home — if you choose sedation, you won't be able to drive yourself afterwards, and most units ask you to bring someone with you.

In the room, step by step

Once you're settled, the team will talk through what is about to happen and check you're comfortable. Many people are offered a spray to numb the back of the throat, sedation through a small vein cannula, or both — the aim is to keep you relaxed while the tube passes. You will usually lie on your side. As the endoscope moves through your food pipe (oesophagus), into your stomach, and on into the first part of the small bowel (the duodenum), the camera sends pictures to a screen in real time. Air is sometimes puffed in gently to open the lining out for a better look, which can leave you feeling a little bloated. If the doctor sees an area that needs a closer look, tiny tissue samples — biopsies — can be taken through the scope; you can see that happening in this site's longer recording of a real gastrointestinal endoscopy with biopsy, filmed over about five and a half minutes.

What the camera can — and can't — tell your doctor

What an endoscopy shows, above all, is the surface: the lining of the food pipe, stomach, and duodenum, in colour and in detail. That direct view can reveal inflammation, ulcers, and other changes that a scan looking from outside the body may not show as clearly, and a biopsy lets a small piece of that lining be examined in a laboratory afterwards. It is a looking and sampling test, not a picture of everything — it doesn't replace blood tests, scans, or your wider clinical assessment, and some findings only become clear once biopsy results come back. Endoscopy of the lower bowel works on the same principle but by a different route, and our separate guide to colonoscopy and how it is done explains that test if you've been offered both.

Straight afterwards, and the days that follow

Most people rest for a short while in a recovery area while any sedation wears off. A mild sore throat or feeling of fullness is common and usually settles on its own. Before you leave, the team will generally tell you what they saw on the day; if biopsies were taken, those results take longer and will be sent on afterwards. Follow the aftercare advice your unit gives you, and contact them — or seek medical help promptly — if you develop severe pain, vomiting, or bleeding after the test rather than waiting it out.

MedicalVideos.com has published trusted medical videos since 2007. The site was founded by Dr. Mohamed Ibrahim, MD, PhD — physician and researcher.

Educational only — this article is general information about endoscopy, not medical advice and not a recommendation for or against any test. Whether you need an endoscopy, and how yours should be prepared for and performed, are decisions for your own doctor and endoscopy unit, who know your history.

Frequently Asked Questions

Is an upper endoscopy the same as a gastroscopy?
Yes, in everyday use the two names describe the same test: a flexible camera passed through the mouth to examine the food pipe, stomach, and first part of the small bowel. You may also see it written as an OGD or EGD, after the structures it examines.

Will I be asleep during the test?
Not usually fully asleep. Many units offer throat spray, sedation, or both, so you stay relaxed and drowsy rather than under a general anaesthetic. What is offered varies between units, and the team will discuss the options with you beforehand.

Why would a biopsy be taken if nothing obvious was seen?
A biopsy takes a tiny sample of the lining so it can be examined under a microscope. That can pick up inflammation or other changes that are not visible to the naked eye, and it can be done even when the lining looks broadly normal.

How long does the examination itself take?
The camera examination is usually a matter of minutes, although the whole appointment — arrival checks, the test, and recovery from any sedation — takes considerably longer. Times vary between units, so allow for the slot your appointment letter gives you.