Preparing for Upper GI Endoscopy: What to Do in 24 Hours

Upper GI endoscopy is one of the commonest and safest procedures in medicine. The preparation is simple: an empty stomach, the right information about your medicines, and someone to take you home.

Procedure guide

Patient education · Reviewed by the treating clinician · Last reviewed January 2026

Why you must fast

There are two reasons, and both matter.

  • Safety. If the stomach contains food or liquid, it can be regurgitated during the procedure and enter the lungs. This is uncommon but potentially serious. An empty stomach greatly reduces that risk.
  • Visibility. Food and liquid obscure the stomach lining. An incomplete examination may mean the test has to be repeated, which nobody wants.

The standard instruction is nothing to eat for about 6–8 hours before the procedure. Clear water is usually permitted up to about two hours before, unless you have been told otherwise. “Clear” means water, and water only — not tea, coffee, milk, juice, soup or oral rehydration solution.

If you are a smoker

Please do not smoke on the morning of the procedure. Smoking increases stomach acid and the risk of regurgitation, and it affects your breathing during sedation.

Your regular medicines

Most medicines can be taken with a small sip of water on the morning of the procedure. Some need specific handling. Please bring your complete medicine list and confirm the plan with the hospital in advance.

MedicineWhat usually happens
Blood pressure tabletsUsually taken as normal with a small sip of water, unless told otherwise
Heart medicinesUsually continued; do not stop without specific advice
Blood thinners (warfarin, apixaban, rivaroxaban, dabigatran, edoxaban, clopidogrel, prasugrel, ticagrelor)May need to be paused or bridged in advance. Must be discussed at booking — this cannot be arranged on the day
InsulinDose is usually adjusted because of the fasting; needs a specific plan
Diabetes tabletsSome are held on the morning of the procedure; certain classes must be stopped in advance for safety
Iron tabletsUsually stopped a few days before, as iron can obscure the view
Asthma inhalersBring them with you and use them as normal

What to tell us beforehand

  • Allergies — particularly to any medicine, latex or adhesive.
  • Pregnancy or the possibility of pregnancy.
  • Heart or lung disease, including previous heart attack, heart failure, COPD or sleep apnoea.
  • Implanted devices — pacemaker, defibrillator, insulin pump.
  • Previous problems with anaesthesia or sedation in you or your family.
  • Loose teeth, dentures or a history of difficult intubation.

The 24 hours before — a simple timeline

  1. Morning, day before: confirm your escort and your transport home. Arrange time off work if needed.
  2. Day before: eat normally unless told otherwise, but avoid very heavy or oily meals late at night.
  3. Evening, day before: take your usual medicines as instructed. If you were told to stop something, confirm you have.
  4. Midnight onwards: nothing to eat.
  5. Morning of the procedure: clear water is usually allowed up to two hours before your appointment time. Blood pressure and heart medicines are usually taken with a small sip.
  6. Arrival: bring your medicine list, previous reports and your escort. Remove nail polish and jewellery.

What happens during the procedure

You will be reviewed by the endoscopist, and the reason for the test and its risks will be explained before you sign the consent form. An intravenous line is placed, and monitoring for oxygen, pulse and blood pressure is attached. Sedation is given, and sometimes a throat spray to numb the back of the throat.

The endoscope passes through the mouth into the food pipe and stomach. It does not obstruct your breathing, because the food pipe and windpipe are separate. The examination typically takes five to fifteen minutes. Biopsies are painless, and a little spotting of blood afterwards is normal. If treatment such as bleeding control or dilatation is needed, the procedure takes longer.

What happens afterwards

  • You rest in the recovery area for about 30–60 minutes until the sedation wears off.
  • A sore throat for a day or two is common and usually settles without treatment.
  • Mild bloating or wind from the air used during the procedure is normal.
  • You can usually eat and drink normally once fully awake, unless advised otherwise.
  • The findings are explained to you before you leave, and you receive a written report.
  • Biopsy results, where taken, take a few days and are discussed at follow-up.

The next 24 hours

  • Do not drive — not a car, not a two-wheeler, and not for the remainder of the day.
  • Do not operate machinery or use power tools.
  • Do not make important decisions or sign legal documents.
  • Do not drink alcohol for 24 hours after sedation.
  • Do not travel alone on public transport; have your escort take you home.

When to call the hospital afterwards

Contact us if you develop

  • Severe or worsening abdominal pain, rather than mild soreness.
  • Vomiting blood, or vomiting that does not settle.
  • Black tarry stools, or a significant amount of blood in stool.
  • Fever, shivering or a rapid pulse.
  • Difficulty breathing or chest pain.
  • Difficulty swallowing that is getting worse rather than better.

Call the hospital on (phone). If it is a genuine emergency and you cannot reach us, go to the nearest emergency department.

Summary checklist

  • Nothing to eat for 6–8 hours; clear water only up to 2 hours before.
  • Confirm which medicines to take, hold or stop — especially blood thinners and diabetes medicines.
  • Bring a responsible adult escort, and do not plan to drive.
  • Bring your medicine list and all previous reports.
  • Allow two to three hours at the hospital.
  • Plan a light day afterwards, with no driving and no decisions.

Please remember

This article is general health information, not personal medical advice. It cannot account for your individual circumstances. Do not start, stop or change any medicine based on it. If you are worried about your symptoms, please book a consultation, and in an emergency seek care immediately.

Book an upper GI endoscopy

Requests are answered by the hospital team. A request is not a confirmed appointment until we contact you.

Questions patients ask

Common questions before an endoscopy

Will I be asleep for the endoscopy?

Usually you will be sedated, meaning you are relaxed or lightly asleep and typically remember little of the procedure. This is different from full general anaesthesia with a breathing tube. The level of sedation is tailored by the endoscopist to your age, weight, other illnesses and the purpose of the procedure. Some patients prefer no sedation at all, using only throat numbing, which is also possible.

Can I have a glass of water on the morning of the procedure?

Clear water is usually allowed up to about two hours before your appointment, unless you have been told otherwise. Milk, tea, coffee, juice, soup and oral rehydration solution are not ‘clear water’ and are not permitted. If in doubt, ask us rather than guessing — the procedure may be postponed if the stomach is not empty.

What if I accidentally eat something?

Tell the hospital immediately — do not hide it. Depending on what and when you ate, the procedure may need to be delayed or rescheduled. Proceeding with a full stomach is a safety risk and also gives a poor view. Being honest is far better than a compromised or unsafe procedure.

Do I have to stop my blood thinner?

Possibly, but this must be decided by a clinician, not by you. Whether to pause or bridge a blood thinner depends on why you take it, the type of medicine, whether a biopsy or polyp removal is planned, and your risk of bleeding versus clotting. Please tell us at booking so a plan can be written. Never stop these medicines on your own.

Is the biopsy going to hurt?

No. A biopsy removes tiny fragments of the surface lining using a small forceps passed through the endoscope. The gut lining does not have the type of pain-sensitive nerves that would make this painful, so you will not feel it. A small amount of spotting afterwards is normal and not usually significant.

What if I cannot arrange an escort?

Please tell us in advance — normally the procedure cannot go ahead under sedation without a responsible adult to take you home. In some cases the procedure can be performed without sedation, using only throat numbing, if that is clinically appropriate. This is a conversation to have at booking, not on the day.

How soon can I eat after the procedure?

Usually as soon as you are fully awake and your swallow reflex is normal, which is often within an hour of the procedure. Start with something light and avoid very hot or spicy food for the first meal. If you were given specific instructions — for example after dilatation or band ligation — follow those instead.

Have questions this article did not answer?

Bring them to your consultation — a short conversation is usually more useful than any amount of reading.