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Dr Ed HalveySpecialist anaesthetist, Perth

Pre-op guidanceFasting

Fasting before your surgery

Fasting means not eating or drinking for a set time before your anaesthetic. It matters for your safety. It lowers the risk of stomach contents entering your lungs while you are under anaesthesia.

Perth, Western Australia
Your hospital will give you exact fasting times. Always follow those. Times can differ depending on your operation, your health, and the time of your surgery. The information below is a general guide only. If your hospital's instructions differ from this page, follow the hospital.
Taking a GLP-1 medicine such as Ozempic, Wegovy or Mounjaro? Your fasting is different from the standard advice on this page. Please follow the GLP-1 medications before surgery guidance instead.

Work out my fasting times

Enter the date and time you have been asked to arrive at hospital (your admission time) to see your fasting times. This is a general guide based on the standard 6-hour and 2-hour rules. Your hospital's exact times still apply.

A general guide for adults

6 hours before
Stop eating solid food, and stop milk or drinks that contain milk (such as a coffee with milk). A light meal is fine up to this point unless told otherwise.
2 hours before
Stop clear fluids. Up until 2 hours before, you may have small amounts of clear fluids: water, clear cordial, pulp-free apple juice, or black tea or coffee (no milk).
On waking, before you leave
If your hospital allows, a few sips of water to take essential medicines is usually fine. Check this with them first.

What counts as a clear fluid?

A clear fluid is one you can see through. Yes: water, clear cordial, black tea or coffee (no milk), pulp-free clear apple juice. No: milk, milky tea or coffee, smoothies, juice with pulp, alcohol.

Under modern fasting guidelines, many clear carbonated soft drinks (for example clear lemonade) are counted as clear fluids. However, some hospitals still ask you to avoid fizzy drinks before surgery. If your hospital's instructions differ from this, follow your hospital.

What counts as food?

Food means anything you eat or chew, including fruit, yoghurt, lollies, mints and chewing gum. Fruit counts as food, so it stops at the same time as a meal. Juice with pulp, such as orange juice, also stops at the same time as food. Clear apple juice with no pulp counts as a clear fluid.

There is no particular food you need to eat before surgery. What matters is when you stop, not what you choose.

Your usual medicines

Keep taking your regular medicines as normal unless you have been told otherwise. Some medicines (for example certain diabetes or blood-thinning medicines) may need to be adjusted before surgery. If you are unsure, ask the hospital, your surgeon, or your GP. Do not stop important medicines without advice.

Other things to avoid

  • No chewing gum or lollies inside the fasting window. They count as eating.
  • No smoking or vaping on the day of your surgery.
  • Do not drink alcohol the night before or the day of surgery.
If you accidentally eat or drink inside your fasting window, do not just turn up. Tell the hospital as soon as you can. Your surgery may need to be delayed for your safety.