The clinical team believe your medical care will be helped if you have a gastroscopy, as this will allow them to see your oesophagus, stomach and the first part of your small bowel. A gastroscopy is also known as an endoscopy or OGD (OesophagoGastro-Duodenoscopy). The gastroscopy will be used to investigate the cause of your symptoms and in some cases, it can also be used to treat any problems seen. This page gives you information about having a gastroscopy and explains the risks and benefits related to the procedure. This will help you to decide if you would like to go ahead with the procedure and whether you would like to have sedation.

What is a gastroscopy?

Gastroscopy is a procedure that looks at the lining of the oesophagus (the gullet), the stomach and around the first bend of the small intestine (the duodenum).

A gastroscope is a long thin flexible tube. It has a tiny digital camera and a bright light at the end which allows the lining of your stomach to be seen.

The gastroscope is passed through the mouth down the gullet and into the stomach. The pictures are transmitted on to a monitor screen where any abnormalities will be seen. The procedure usually takes from 5 to 15 minutes.

Within the PDF below, see Figure 1: Diagram of the gut

Your doctor or the endoscopist will explain about any complications and risks involved with the procedure.

A consent form must be completed before having the gastroscopy. If you have any questions, please ask a member of the medical team before signing the form.

A member of your medical team will also sign the form.

By signing the consent form you are agreeing to have the procedure and that you understand why it is needed. This does not take away your right to change your mind or have the test stopped at any time.

Preparing for your procedure

To allow a clear view during the procedure the stomach must be completely empty. Most patients will be asked not to have anything to eat for at least 6 hours before their appointment time. You may drink water up to 2 hours before your appointment time.

If you are unwell before the procedure, for example, if you have been vomiting a lot, the doctor or nurse will advise you to remain ‘Nil by mouth’. This means that you must not eat or drink anything until after the gastroscopy.

The doctor may decide that you need an intravenous infusion or ‘drip’ to keep you hydrated. This will allow fluid to be given into your bloodstream through a small tube placed into your arm.

Anaesthetic throat spray

Throat spray is a local anaesthetic spray used to numb the throat. This can be given on its own or alongside sedation.

The throat spray has an effect very much like a dental injection.

You must not have anything to eat or drink for about 30 minutes after the procedure. This will allow for the sensation in your mouth and throat to return to normal.

It is strongly advised that your first drink after the procedure should be cold. This should be sipped slowly to make sure that you do not choke.

The nurses will complete an endoscopy checklist before you leave the ward to have the procedure.

The nurses and ward doctors are happy to try and answer any questions you may have.

You can wear your own clothes for the gastroscopy.

In the Endoscopy Department

Each patient will be seen by a nurse who will look at the completed checklist and confirm your personal details and record any allergies you may have. You will also be asked if you understand the procedure and have signed a consent form. Your blood pressure, pulse, temperature and oxygen levels will also be checked.

Anaesthetic throat spray

You will be offered a choice of sedation and/or throat spray. Intravenous sedation and/or local anaesthetic throat spray can help to keep you comfortable during the procedure.

As gastroscopes have become thinner many patients are happy for the procedure to be carried out without sedation and to have throat spray instead. The throat spray has an effect very much like a dental injection.

The benefit of choosing throat spray is that you are fully conscious (awake) and aware during the procedure.

The only restriction is that you must not have anything to eat or drink for about an hour after the procedure. This is to allow time for the sensation in your mouth and throat to return to normal.

It is strongly advised that your first drink after the procedure should be cold. This should be sipped slowly to make sure that you do not choke.

Intravenous sedation

If you have sedation, it will be given into a vein in your hand or arm. Sedation will make you lightly drowsy and relaxed but not unconscious (asleep). This is called conscious sedation. You will be drowsy but you will still hear what is said to you and will be able to follow simple instructions during the procedure.

Sedation also makes it unlikely that you will remember anything about the procedure. You will be able to breathe normally throughout the procedure.

While you are sedated, we will check your breathing and heart rate, any changes will be noted and dealt with accordingly. For this reason, you will be connected by a probe on your finger to a pulse oximeter which measures your oxygen levels and heart rate during the procedure. Your blood pressure will also be recorded.

Please note that if you have had sedation and are discharged within 24 hours of having the procedure, you must not drive, drink alcohol, operate heavy machinery or sign any legally binding documents. You will also need someone to accompany you home and stay with you for this 24 hour period.

The procedure

Before starting the procedure, any dentures will be removed and the local anaesthetic will be sprayed to the back of your throat. You will then be made comfortable on a patient trolley, lying on your left side. If you have requested sedation this will be the time it is given.

To protect your teeth and the gastroscope, a plastic mouthpiece will be put between your teeth or gums if your dentures have been removed. The tube will then be inserted through the mouth piece. When it reaches the back of your throat, you may be asked to swallow to help the tube go down into the stomach. This will not interfere with your breathing.

Some air will be passed through the instrument. This will expand your stomach and allow a clearer view. You may feel wind like discomfort and belch some air up during the procedure. Please do not be embarrassed.

Any saliva in your mouth will be removed, by the nurse caring for you, using a small suction tube. When the gastroscope is taken out most of the remaining air in the stomach will also be removed. The gastroscopy normally takes between 5 and 15 minutes.

Additional procedures

Further procedures may be needed as part of your care by the endoscopist. Some of the common procedures are outlined on the following pages.


Sometimes the endoscopist will take a biopsy. This is a small sample of tissue that is removed painlessly through the gastroscope using tiny forceps. The sample will be sent to the laboratory for examination. The results can take up to 3 weeks to process, the ward consultant will write to you if you do not have an outpatient appointment planned. The results will also be sent to your GP.

Treatments for bleeding


This is a way to treat oesophageal varices, these are like varicose veins in your oesophagus. The endoscopists will place special elastic bands around each of the varices. This stops the blood supply to these veins and they will eventually disappear. This will not affect the normal blood supply to the oesophagus.


This is a metallic clip placed directly onto a blood vessel to stop the bleeding.

Adrenaline injection

This is an injection of adrenaline at the base of a bleeding blood vessel which causes the vessel to shrink and stop bleeding.


This is used to seal the edges of any bleeding vessel together.


This is a specialised powder spray which can be used to cover a bleeding area and help clotting to stop further bleeding.

Heater probe

This is an instrument that can be used through the endoscope which applies heat to the bleeding areas, causing clotting and preventing further bleeding.



A dilatation can be performed if a narrowing of the gullet is found. This means stretching the narrowing to improve swallowing.


An oesophageal stent is a tube made of a flexible metal which allows it to expand inside the oesophagus, holding it open. This will make it easier for you to swallow food and fluids. Your consultant will choose the right stent and size for your needs.


Complications are not common in gastroscopy.

Minor complications with sedation happen 1 in every 200 examinations. A few people are sensitive to the sedation we use and become too sleepy. This effect can be quickly reversed with another medication.

Major complications associated with having a gastroscopy are very rare about 1 in 10,000. Death is extremely rare, about 1 in 30,000.

The main serious side-effect, about 1 in 20,000, is perforation (a tear) of the oesophagus (gullet) which would normally need an operation and a stay in hospital. This complication is more common if a stretch is performed for narrowing of the gullet, about 1 in every 200 procedures. Stretching of the gullet without discussion or warning before the procedure is only performed in very rare cases.

After the procedure

After the gastroscopy you will be taken to the recovery area until you are ready to go back to the ward. You may feel some bloating in your abdomen.

The endoscopist will talk to you after the procedure, but you may not remember the information if you have had sedation. The ward staff will be able to show you the report on your return to the ward.

Your ward doctors will receive a report containing the results of the procedure and any recommendations made by the endoscopist.

Alternative procedures

The main alternative to a gastroscopy is a barium meal X-ray. A barium meal does not allow the lining of the stomach to be seen in detail or for tissue samples to be taken.

Contact information

Endoscopy Unit

Cheltenham General Hospital

Tel: 0300 422 3593

Monday to Friday, 7:30am to 6:30pm

Gloucestershire Royal Hospital

Tel: 0300 422 8222

Monday to Friday, 08:00 to 6:30pm

Printable version of this page

Having a gastroscopy (OGD) as an inpatient GHPI1477_09_23 Department: Endoscopy Review due: September 2026 PDF, 351.0 KB, 7 pages
Reference number GHPI1477_09_23
Department Endoscopy
Review due September 2026