Gastroscopy is a diagnostic endoscopic examination that examines the upper part of the gastrointestinal tract from the esophagus to the duodenum. It is considered a minimal invasive procedure, as it does not require an incision in the body and does not require significant recovery after the procedure.
The examination is usually performed after the intravenous administration of special drugs that cause sedation under the constant supervision of the patient’s vital cardiorespiratory parameters. In this way a calm and mainly painless and detailed examination for the patient is achieved. If the patient does not want sedation, the procedure can be well tolerated just with the use of a local anesthetic such as lidocaine gel.
During the gastroscopy, the patients, who should be fasting for 6-8 hours, lies on their left side with their head resting comfortably on a pillow. An oral guard is placed between the teeth to prevent the patient from biting the endoscope. After the patient has fallen asleep, the endoscope is passed over the tongue into the oropharynx. Quick and gentle handling leads the endoscope to the esophagus. The endoscope progressively progresses to the esophagus noting any pathology. The endoscope then passes rapidly through the stomach and through the pylorus to examine the first and second portions of the duodenum. Once this is complete, the endoscope is withdrawn into the stomach and a more thorough examination is performed. During the examination, the surface (mucosa) of the esophagus, stomach and duodenum is thoroughly checked and additional procedures are performed, such as biopsies or therapeutic interventions. The air in the stomach is sucked in before the endoscope is removed.
Gastroscopy is a useful examination for
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The diagnosis
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Monitoring
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Performing biopsies
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Treatment
of various disorders and lesions of the upper gastrointestinal tract.
Complications during gastroscopy are rare (<1 ‰).
Note: This article does not substitute a detailed discussion of the procedure with your gastroenterologist.
- Examination time: 5 to 10 minutes
- Allow about 2 hours in total with preparation and recovery
- Biopsies are taken even when the mucosa appears normal
- No driving for the rest of the day after sedation
Findings that commonly arise at gastroscopy are covered separately, including gastritis and Helicobacter pylori, reflux and Barrett oesophagus and coeliac disease, which is diagnosed on duodenal biopsies even when the mucosa looks normal.
Frequently asked questions
How long does a gastroscopy take?
The examination itself usually takes 5 to 10 minutes. With preparation and recovery after sedation, patients should allow around 2 hours in total. Fasting is required beforehand for the period specified.
Is it painful?
Not when performed under sedation, which is the usual practice. Without sedation the main sensation is gagging rather than pain, and a local anaesthetic spray is used for the throat. If sedation is given, driving is not permitted for the rest of the day and someone must accompany you.
Why are biopsies taken when everything looks normal?
Because several conditions are invisible to the naked eye. Eosinophilic oesophagitis, coeliac disease and Helicobacter pylori infection are diagnosed histologically, and the mucosa can appear entirely normal. Biopsies are therefore taken by protocol rather than only when something looks abnormal.
Sources
- European Society of Gastrointestinal Endoscopy, Management of epithelial precancerous conditions and early neoplasia of the stomach (MAPS III). https://pubmed.ncbi.nlm.nih.gov/40112834/
Content last updated: September 2026 (15/09/2026).
