A gastroscopy is a procedure that lets a doctor look directly inside your upper digestive tract using a thin, flexible tube with a tiny camera on the end. Formally called an esophagogastroduodenoscopy (EGD), it examines three structures: your esophagus (the tube connecting your throat to your stomach), your stomach, and your duodenum (the first section of your small intestine). The whole procedure typically takes 15 to 30 minutes, and you go home the same day.
Why Doctors Order a Gastroscopy
A gastroscopy is one of the most common procedures in gastroenterology, used both to diagnose problems and, in some cases, to treat them on the spot. It’s typically recommended when you have upper digestive symptoms that haven’t been explained by other tests. Common reasons include:
- Difficulty swallowing or a sensation of food getting stuck
- Persistent upper abdominal pain or chest pain that isn’t heart-related
- Unexplained weight loss
- Ongoing vomiting without a clear cause
- Bleeding in the upper digestive tract, which might show up as vomiting blood or dark, tarry stools
Beyond investigating symptoms, a gastroscopy can identify specific conditions: acid reflux disease (GERD), stomach ulcers, narrowed or blocked passages, enlarged veins in the esophagus, hiatal hernias, celiac disease, Crohn’s disease affecting the upper gut, infections, and tumors (both cancerous and non-cancerous). It’s also used to monitor the digestive tract after surgery.
How to Prepare
You’ll need an empty stomach for the procedure to work properly. Most clinics ask you to stop eating solid food at least six to eight hours beforehand, with clear liquids allowed up to a few hours before your appointment. If you take blood-thinning medications, your doctor will give you specific instructions on whether to pause them, since even routine biopsies carry a small bleeding risk. Bring someone with you to drive you home, because the sedation used during the procedure will leave you too drowsy to drive safely for the rest of the day.
What Happens During the Procedure
You’ll lie on your back or side on an exam table. Monitors will track your heart rate, blood pressure, and breathing throughout. Before the scope goes in, a numbing spray is applied to the back of your throat to reduce the gag reflex. Most people also receive a sedative through a vein in the forearm, which makes you relaxed and drowsy but not fully unconscious.
A plastic mouth guard is placed between your teeth to keep your mouth open and protect both you and the scope. The doctor then guides the endoscope, a flexible tube roughly the width of a finger, into your mouth and asks you to swallow as it passes down your throat. This is the part most people worry about, but the sedation and throat spray make it far more comfortable than it sounds.
Once inside, the camera at the tip sends a live video feed to a monitor, giving the doctor a detailed, close-up view of the lining of your esophagus, stomach, and duodenum. Gentle air pressure is pumped through the scope to inflate your digestive tract slightly, which helps open up the folds and gives a clearer picture. If anything looks abnormal, the doctor can pass tiny instruments through the scope to take tissue samples (biopsies) for lab analysis. Small polyps under about 5 millimeters can be removed right then using biopsy forceps. Larger growths require different removal techniques, but those are typically planned for a separate session. When the exam is complete, the scope is slowly withdrawn through your mouth.
How Accurate Is It?
Gastroscopy is highly reliable for detecting problems in the upper digestive tract. For gastric cancer specifically, studies show a sensitivity of about 93% and a specificity of 100%, meaning it correctly identifies the vast majority of cancers and almost never flags healthy tissue as cancerous. A small percentage of cancers, roughly 4.6% in one study of 284 patients, were missed on initial gastroscopy and diagnosed later, typically about 11.5 months down the line. This is one reason doctors may recommend a repeat procedure if symptoms persist despite a normal result.
Risks and Complications
Gastroscopy is considered very safe. The most serious potential complication, a perforation (a small tear in the wall of the digestive tract), occurs in roughly 1 in 2,500 to 1 in 11,000 diagnostic procedures. Clinically significant bleeding after a biopsy is exceedingly rare, limited mostly to isolated case reports. Minor side effects are much more common: a sore throat, mild bloating from the air pumped in during the procedure, and slight nausea as the sedation wears off. These typically resolve within a day.
Recovery and What to Expect After
You’ll spend 30 minutes to an hour in a recovery area while the sedation fades. Your throat may feel scratchy or mildly sore for a day or two, and you might feel bloated or gassy from the air introduced during the exam. Both are normal and pass quickly.
Because of the sedation, you won’t be able to drive, operate machinery, or make important decisions for the rest of the day. Plan to have someone take you home and to take it easy. Most people can eat and drink within a few hours once the numbness in their throat wears off, starting with soft foods and working back to their normal diet. If biopsies were taken, results usually come back within a few days to two weeks depending on what the lab is testing for. Your doctor will typically share any visible findings with you (or whoever brought you) before you leave, with biopsy results to follow later.