Having a gastroscopy


If you have a gastroscopy to examine the upper part of your digestive system, it helps to know what to expect. The procedure only takes about 5 to 15 minutes. You have a choice of pain relief options.

Do not eat or drink anything for 6 hours before the test. You can take small sips of water up to 2 hours before your appointment.

When you arrive at the endoscopy unit

When you arrive in the unit, you sit in the waiting area until a nurse is ready to see you. They ask about your medical history. Please tell the nurse if you had any reactions or allergies to past tests.

You do not need to get changed for the procedure. However, we might ask you to wear a gown over your clothes to protect them. We then take you to a second waiting area.

Your endoscopist explains more about the procedure and answers any questions you have. 

We do everything that we can to avoid you waiting any longer than necessary. However, each procedure takes a different amount of time. This means that it is hard to give exact timings.

We update you about how long you are likely to be in the department. Please be prepared to stay with us for the whole morning or afternoon.

Sometimes, a patient who arrived after you might have their procedure before you. This does not mean that we have forgotten you. It is likely that the other person is on a different list to you.

We sometimes have to deal with emergencies first and might ask you to wait. Apologies in advance if this happens, but please be patient and check at the reception desk if you are concerned.

Choosing sedation or throat spray

You can choose to have this procedure with either:

  • a local anaesthetic spray to make your throat numb
  • sedation, where you stay awake but feel sleepy (drowsy) and calm

You do not usually have a general anaesthetic (a medicine that makes you sleep) for this procedure.

The advantages of having the numbing throat spray are that you:

  • can go home immediately after the procedure
  • do not need a family member or friend to take you home
  • can drive yourself home after the test
  • can return to work after the test

If you have sedation, you are awake for the procedure but the sedative relaxes you and helps to reduce anxiety. Each person reacts to sedation in their own way and might have different levels of drowsiness. You might not remember the procedure or conversations that happen.

    If you decide to have sedation, you must arrange for a family member or friend to take you home about 1 hour after the test. 

    Read more about recovering from sedation.

    During the procedure

    You have the test in one of the procedure rooms. A nurse asks you to take off your shoes, loosen any tight clothes and remove any false teeth and glasses. You need to keep your belongings with you at all times.

    If you decide to have sedation, we put a small tube into your arm or hand using a needle. We give you an injection through this tube.

    Otherwise, we give you a local anaesthetic spray to make the back of your throat numb. This reduces the feeling (sensation) in your throat. You still get the sensation of gagging and retching. This is a natural response to the tube touching the back of your throat.

    You lie on your left side on a trolley. A nurse stays with you throughout the test.

    To keep your mouth slightly open, we put a mouthpiece between your teeth. The nurse might hold the mouthpiece in your mouth. They have a device called a sucker to remove any saliva in your mouth.

    We gently put the tube into your mouth through the mouthpiece and pass it down into your stomach. The endoscopist pushes some air down the tube to get a clearer view. This might make you feel slightly bloated (when your stomach feels full), but it is not painful.

    Sometimes, we take small tissue samples. This is called a biopsy. We remove the tissue through the tube using tiny forceps (a pair of pincers or tweezers). Rarely, this might be uncomfortable but the discomfort should pass quickly. You will probably only feel a tugging sensation. 

    The test usually lasts 5 to 15 minutes. When it is finished, we remove the tube quickly and painlessly.

    Resource number: 2044/VER6
    Last reviewed: July 2021
    Next review: July 2024

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    Contact us


    If you need to change or cancel your appointment, please call 020 7188 8887.

    Questions, problems or concerns

    Please contact the endoscopy unit staff for advice from Monday to Saturday, 9am to 5pm.

    Nurse in charge: 020 7188 7188 ext 54059

    St Thomas' reception desk: 020 7188 7188 ext 54046

    In an emergency, out of hours

    Out of hours means 6pm until 8am the next day and on Saturday or Sunday.

    Phone 020 7188 7188 and ask to be put through to the on-call gastroenterology registrar (through an application called RotaWatch).

    Do you have any comments or concerns about your care?

    Contact our Patient Advice and Liaison Service (PALS)

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