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What is OGD? 

An oesophago-gastroduodenoscopy (OGD), also sometimes known as a gastroscopy, is an examination of your oesophagus (gullet / food pipe), stomach, and duodenum (the first and second part of your small bowel). 

We put a long, thin, flexible tube called an endoscope into your mouth and pass it down into your stomach. The endoscope is about the thickness of your little finger and has a mini video camera built into its tip, which sends pictures of the inside of your stomach and intestine to a video screen. 

Why do I need this test? 

Your GP or hospital specialist has recommended you have this test to investigate the cause of your symptoms. There are many reasons for this investigation including: indigestion, anaemia, weight loss, vomiting, passing black motions, vomiting blood or difficulty swallowing. 

What are the alternatives? 

An OGD lets us look directly inside your gullet, stomach and some part of the small bowel (duodenum). For some conditions it also allows us to take small samples for testing (biopsies) which will help us reach the diagnosis. In some circumstances a barium swallow can be offered. A doctor or nurse can advise you if this is appropriate. 

What are the benefits? 

An OGD can provide a diagnosis on the day. This may be available on the day. 
If the endoscopist has taken a biopsy, it will take some time for this to be processed. Your referring doctor or nurse will review the results of the biopsy and will provide further advice. 

What are the risks? 

An OGD is an extremely safe procedure. Complications are very rare but the following may occur: 

  • Sore throat: Your throat may be sore for a day or two after the procedure. This is not serious and will get better, you can take over the counter throat lozenges to ease the pain. 
  • Dislodged teeth, crowns or bridgework: there is a small chance that loose teeth, crowns or bridgework can be dislodged during the procedure. If you have any of these let the endoscopist know beforehand. 
  • Bleeding: it is common to have some bleeding after a biopsy. This lasts no more than a few seconds. The risk of major bleeding (more than half a cupful of blood) is less than 1 in 1,000 and requires medical attention. 
  • Perforation: the risk of making a perforation (small hole) during this test is less than 1 in 10,000. The risk is greater 1:500 if we find a narrowing or a cancer. The risk of perforation after dilation is 1:100 if we carry out a procedure to stretch the oesophagus. We take every care to avoid perforation, but if it happens you will need to stay in hospital and may need surgery to repair the hole. 
  • Pneumonia: if you are frail or have very severe breathing problems such as COPD or emphysema, you may develop pneumonia after the test. 
  • Reaction to the sedative: we give the smallest possible dose of sedative to prevent you from having any side effects. Sedatives can reduce your rate of breathing or cause your heart rate to slow down. If you do have a reaction, you will be given a medication to reverse the effect of the sedative. 
  • Failure to complete: occasionally, the procedure may need to be abandoned or may be incomplete; for example, if you find the procedure too uncomfortable or if the stomach has some food contents to proceed safely with your procedure. In this case, the procedure may need to be repeated or we may suggest an alternative procedure. 

Sedation and anaesthetic throat spray 

Intravenous sedation and / or topical local anaesthetic throat spray can improve your comfort during the procedure so that the endoscopist can perform the procedure successfully. 

Anaesthetic throat spray only 

The throat is numbed with a local anaesthetic spray. The benefit of choosing the throat spray is that you are fully conscious and aware and can go home unaccompanied almost immediately after the procedure. You are permitted to drive and function as normal afterwards. 

Intravenous sedation and anaesthetic throat spray 

The throat spray is given as above and, in addition, a light sedative is given via a cannula (small plastic tube). The sedative should make you feel slightly drowsy and relaxed but will not ‘knock you out’ or make you unconscious. You will be in a state called co-operative sedation. This means that, although drowsy, you will still hear what is said to you and therefore will be able to follow simple instructions 
during the investigation.

You will be able to breathe quite normally throughout. If you have a sedative, someone must come to collect you and stay with you overnight. You will not 
be allowed to go home on your own in a taxi. If you cannot arrange this, we will have to cancel your OGD. 

What are the after-effects of the sedative? 

If you have had a sedative, you may feel tired, dizzy or weak. 
If you have had sedation, for 24 hours after your procedure you must not: 

  • Drive 
  • Operate potentially dangerous machinery 
  • Drink any alcohol 
  • Take sleeping tablets or recreational drugs 
  • Use potentially dangerous appliances such as a cooker or kettle 
  • Have a bath unsupervised 
  • Look after dependents on your own 
  • Go to work 
  • Sign any legal documents 

Do I need to stop taking my medication? 

If you take blood thinning medication you may need to stop taking them for a short time. If you have not been advised whether you need to stop or continue to take them, please contact us.  
If you are diabetic, please read the advice sheet, if you have not received this please ring the booking office and we will send you a copy. 

Important Notice for Patients on Weight Loss Injections  (Mounjaro, Wegovy or Ozempic) 

If you are currently receiving weight loss injections, please stop this treatment one week prior to your scheduled endoscopy procedure. 
For any questions or concerns, please contact the Endoscopy Nursing Team: 

Do I need to prepare? 

  • We need to get a clear view, so your stomach must be empty.  
  • Do not eat anything for six hours.  
  • You can have clear fluids such as water or black tea up to three hours before the procedure.  
  • Please wear comfortable, loose clothing when you come for the procedure 
  • If you need an interpreter, please contact us as soon as possible so we can make the necessary arrangements. 

What should I bring with me? 

  • The name and contact number of the person collecting you. 
  • A list of medications including herbal and over the counter medications 
  • A list of allergies to medication, food or substances 
  • Essential medications such as insulin, Parkinson’s medication, epilepsy medications etc. 
  • Please do not bring any valuables with you. The hospital cannot accept responsibility for the loss or damage to personal property during your stay in endoscopy. 

What happens when I arrive? 

Please note that your appointment time is the time that you should arrive in the department. It is not the time of your actual procedure. We recommend that you plan to be with us for the whole morning or afternoon, depending on your time slot. 

When you arrive, a nurse will fill out an assessment form with you to ask about your arrangements for getting home. If you have sedation someone must come to the endoscopy unit; collect you and stay with you overnight. You will not be allowed to go home on your own in a taxi. 

The nurse will check your temperature, blood pressure, pulse, respiration rate and oxygen levels. If applicable the nurse will check your INR and blood sugar levels. If you choose to have sedation a nurse will put a cannula (small plastic tube) into a vein usually on the back of your hand, through which the endoscopist will administer sedation. 

Consent 

We must, by law, obtain your written consent to any procedures beforehand. We want to involve you in decisions about your care and treatment. Staff will explain all the risks, benefits and alternatives. If you decide to go ahead, we will ask you to sign a consent form. If you are unsure about any aspect of the treatment proposed, please do not hesitate to speak with a member of staff. 

What happens before the test? 

A nurse will take you into the endoscopy procedure room and make you comfortable on an examination trolley. The nursing team will confirm your details again as part of our safety check list. 
The nurse will then monitor your blood pressure, pulse, respiration rate, oxygen levels and temperature. A nurse or endoscopist will give the anesthetic throat spray and ask you to lie down on your left side. 
A nurse will put a mouthguard in your mouth and ask you to bite gently on it. This makes it easier for the endoscope to pass down your throat.  
If you have a sedative, you will be given it just before the start of the test. Oxygen will be given through a sponge placed in your nostril. 

What happens during the test? 

A nurse will always be with you during your procedure to reassure you, talk through what is happening and clear saliva (spit) from your mouth using yanker suction. 

It is important to remember the endoscope is passed into your food pipe and not into your lungs. You are still able to breathe normally, and the nurse may ask you to concentrate on this during the procedure. 

The endoscopist will gently put the endoscope into your mouth and pass it down into your stomach. 
They will view images of your oesophagus, stomach and the upper part of your small intestine on a screen. 

If the endoscopist takes biopsies, you will not feel this at all. They will tell you if they take any. Medical photographs are taken during the test for the report. 

How long will it take? 

It usually takes no longer than 10 minutes. How long it takes you to recover depends on whether you have had a sedative. 

What happens after the test? 

Patients with morning appointments should be ready to be discharged from the unit between 11am and 1pm. Patients with afternoon appointments should be ready for discharge between 4pm and 6pm. 
Your throat may feel slightly sore. After resting you will be given a drink and some biscuits. You may feel a little bloated due to the air blowing in through the tube. This will quickly pass. You will have an opportunity to discuss your results before you go home. 
If you have had a sedative injection, you will need to stay until this has worn off. This usually takes at least 30 – 45 minutes. For this reason, you must have someone who can collect you from the Unit, take you home and look after you overnight. However, you may resume eating as normal. 
If you have not had a sedative, you can leave as soon as you are ready. A nurse will give you any necessary paperwork before you leave the department. We will also send a copy of the report to your GP or the hospital specialist. 

What happens when I go home? 

The anaesthetic throat spray takes about 45 – 60 minutes to wear off, so please do not eat or drink anything for one hour after your procedure. When this time comes, start by taking sips of cool water. 
If you swallow these easily, you can eat and drink normally. You should be able to take your regular medication unless you have been advised otherwise. 

Care provided by trainees 

Our department supports clinical training and so there may be a trainee nurse or doctor assigned to the procedure list. We will make the investigation as comfortable as possible for you. If you do not wish to have your care or procedure undertaken by a trainee, please advise the staff. Neither your treatment nor timings will be affected by your decision. 

When to seek help after the test 

Please do not hesitate to contact us if you are worried about any symptoms you may have after this test.

If you experience severe abdominal pain, if you pass black tarry stools, if you have a fever or hot and cold sweats, please seek help immediately. 

If you are concerned or distressed by the symptoms, the priority will be to return to hospital to be seen in the Emergency Department. However, if there is time and you or your family members are able, please also consider phoning our nursing team. 

Frimley Park Hospital 

For medication queries, please contact the nursing team between 8am–1pm Monday to Friday: 

Heatherwood Hospital 

  • For medication queries, please contact the nursing team between 9am-4pm Monday to Friday Endoscopy Unit, Heatherwood Hospital: 0300 614 4020  
  • For appointment queries or to request information leaflets, including diabetic leaflets, contact the admin team: Endoscopy booking for Heatherwood Hospital: 0300 614 4009 

Wexham Park Hospital 

  • For medication queries, please contact the nursing team between 9am-4pm Monday to Friday 

Lady Sobell Unit, Wexham Park Hospital: 0300 615 4163 
Endoscopy Suite, Wexham Park Hospital: 0300 615 9448 

Contact us

If you have any queries relating to this information, please contact the Endoscopy service.

About this information

Service:
Endoscopy

Reference:
H/051

Approval date:
7 July 2025

Review date:
1 July 2028

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