Upper Endoscopy (Gastroscopy): Why, How, and What to Expect

What is an upper endoscopy?

An upper endoscopy - also called a gastroscopy - is a test in which a thin, flexible tube with a small camera on the tip (an endoscope) is passed through the mouth to look at the esophagus (food pipe), stomach, and the first part of the small intestine (duodenum). The camera sends a clear picture to a screen, so the doctor can examine the lining directly.

Why it is done

Your doctor may recommend a gastroscopy to look into symptoms or to screen when there is a reason to. Common reasons include:

• Ongoing heartburn, acid reflux, or difficulty swallowing.
• Persistent upper-abdominal pain, nausea, or indigestion.
• Unexplained anaemia or signs of bleeding.
• Checking for H. pylori (a common stomach bacterium), inflammation, or ulcers.
• Following up known conditions over time.

During the test, the doctor can also take a tiny tissue sample (a biopsy), which is a routine part of many endoscopies and is not something you feel.

How to prepare

Preparation is straightforward, and we will give you specific instructions when you book:

• Fasting: an empty stomach is essential for a clear, safe view. This usually means no food for around 6-8 hours beforehand, with clear-fluid guidance up to a set time.
• Medications: tell us about all your medications, especially blood thinners and diabetes medicines, as some may need adjusting. Do not stop anything without asking us first.
• Arrange support: if you choose sedation, you will need someone to accompany you home and should not drive for the rest of the day.

What happens on the day

The examination itself is usually short - often around 10 to 15 minutes.

1. Check-in and consent. The team reviews your history and answers questions.

2. Comfort options. A numbing throat spray and, in many cases, light sedation are offered so the test is as comfortable as possible. It is usually well tolerated.

3. The examination. You lie on your side. The endoscope is passed gently through the mouth; it does not interfere with breathing.

4. Recovery. You rest until any sedation wears off. Most people go home the same day.

We use internationally accredited techniques and equipment, and everything is explained as we go.

After the test

You may have a mildly sore throat or feel a little bloated with air for a short time - this usually settles quickly. If sedation was used, plan to rest for the day. The doctor will share initial findings, and any biopsy results follow later. We will explain what the findings mean for you and any next steps.

When should you call us? Contact us promptly if you have significant chest or abdominal pain, difficulty swallowing, black stools, vomiting blood, or a fever after the procedure. These are uncommon, but worth acting on quickly.

Talk it through with us

If a gastroscopy has been suggested, or you have symptoms you would like assessed, it helps to plan it around your history. To plan a check-up that fits your history and goals, our medical team can help. Contact us on LINE (@younifyclinic) or WhatsApp +66 81 556 9696.

YOUNIFY Clinic - 2nd Floor, Room 214, United Center Building, 323 Silom Road, Silom, Bang Rak, Bangkok 10500. Open daily 11:00–20:00.