A gastroscopy (also called an OGD or upper endoscopy) examines the food pipe (oesophagus), the stomach and the first part of the small intestine (duodenum). A thin, flexible tube with a camera at its tip is passed gently through the mouth. It is usually done as a day procedure under light sedation.
Why it is done
- Indigestion, upper abdominal pain or bloating that does not settle
- Reflux or heartburn that persists despite treatment, or difficulty swallowing
- Vomiting blood, black stools, or anaemia
- Unexplained weight loss or loss of appetite
- Testing for H. pylori and checking the stomach lining. See H. pylori and gastritis.
- Screening for stomach cancer in people at higher risk. See stomach cancer screening.
- Follow-up of known conditions such as Barrett’s oesophagus or intestinal metaplasia
Before the procedure
- No food for about six hours beforehand. Small sips of water are usually allowed up to two hours before.
- Tell the clinic about blood thinners, diabetes medicines and allergies. Some medicines need to be adjusted or paused.
- Arrange for someone to accompany you home, because of the sedation.
Print the gastroscopy preparation sheet to fill in your times.
During the procedure
A spray may be used to numb the throat, and a small mouth guard protects your teeth. With sedation, most people sleep lightly through the procedure and remember little of it. The examination itself usually takes about 10 to 15 minutes. Small tissue samples (biopsies) can be taken painlessly, for example to test for H. pylori or to check the stomach lining.
After the procedure
You rest for a short while as the sedation wears off, and Dr Chia explains what was seen. A mild sore throat or some bloating is common and settles within a day. Because of the sedation, you should not drive, operate machinery or sign important documents for the rest of the day. Biopsy results usually take a few days.
Is it safe?
Gastroscopy is a common and generally safe procedure. Serious complications, such as bleeding or a tear (perforation), are rare, and are a little more likely when treatment such as polyp removal or stretching of a narrowing is done. Seek medical attention promptly if you develop severe pain, fever, black stools or vomiting blood after the procedure.
A gastroscopy and a colonoscopy can be done in the same session, under one sedation. Dr Chia will advise whether you need one or both.
Insurance
Dr Chia is on the specialist panels of AIA, Great Eastern, HSBC Life, Income, Prudential, Raffles Shield and Singlife for Integrated Shield Plans, and on many corporate insurance panels (see all panels). Check your coverage with your insurer.
General information only. Reviewed by Dr Chia Chung King, 2026-11-07. Book a consultation.