Healthdirect Free Australian health advice you can count on.

Medical problem? Call 1800 022 222. If you need urgent medical help, call triple zero immediately

healthdirect Australia is a free service where you can talk to a nurse or doctor who can help you know what to do.

beginning of content

General anaesthetic

5-minute read

Key facts

  • A general anaesthetic makes you unconscious during surgery, so you won’t be aware, move or feel pain.
  • Medicines are given through a drip in your vein and through a breathing mask.
  • Tell your anaesthetist about your health, allergies, medicines and any past problems with anaesthetics.
  • You will need to fast before a general anaesthetic.
  • You might feel tired, nauseous or cold or have a sore throat for a short time after the anaesthetic.

What is a general anaesthetic?

A general anaesthetic uses medicines to make you unconscious so you will not feel pain, move or be aware during surgery.

Why might I need a general anaesthetic?

General anaesthetics are used for major and some minor operations. Some operations can only be done under general anaesthetic.

Alternatives to a general anaesthetic are:

  • local anaesthetic, which numbs a small part of your body
  • regional anaesthetic, which numbs a whole area of your body
  • sedation, which makes you sleepy

The best anaesthetic for you depends on the procedure, your health and your and your doctors’ preferences. You can discuss this with your doctor or anaesthetist before surgery.

Sometimes children have a general anaesthetic to help them keep still for a procedure, such as an MRI.

How do I prepare for a general anaesthetic?

Meeting your anaesthetist

You will usually meet with your anaesthetist before the surgery. This might be in the few days before your surgery, especially if you are having major surgery or have any health concerns. Usually, it will be in the hours before surgery.

Your anaesthetist will ask you about your health and if you or your family have had any problems with anaesthetics in the past. They may also ask about the medicines you take, whether you have allergies and whether or not you smoke. You should provide any medical information you may have from a previous anaesthetist.

They might examine your mouth, teeth and veins and may listen to your heart and lungs.

Your anaesthetist will explain the type of anaesthetic you will have and what could possibly go wrong. They may ask you to sign a consent form. The form says you agree to the anaesthetic and understand why you are having it and the risks involved.

Your anaesthetist may arrange tests to prepare you for surgery.

You should discuss any questions or concerns with your anaesthetist.

Before surgery

You will need to fast before you have a general anaesthetic. This is so you do not vomit up food in your stomach and inhale it into your lungs (known as aspiration). This can cause serious complications. Your anaesthetist will tell you when you need to start fasting.

They may advise you:

  • what medicines you should not take before and on the day of surgery
  • not to drink alcohol from the day before surgery
  • to quit smoking before surgery
  • not to use drugs for at least a week before surgery

How will I get my general anaesthetic?

In most cases, you will receive the general anaesthetic as an injection into a vein on the back of your hand, through a thin plastic tube called a cannula. Sometimes, you will inhale (breathe in) an anaesthetic gas through a mask.

During surgery, your anaesthetist will monitor your level of consciousness, breathing, oxygen level, heart rate and blood pressure. They will usually put a breathing tube into your mouth and give you oxygen.

They will continue giving you anaesthetic medicines through your vein or through a mask to keep you unconscious. Your anaesthetist can adjust the amount of anaesthetic you receive based on what your need at the time.

What happens once I wake up from my anaesthetic?

When you wake from the general anaesthetic, you might feel sleepy, nauseous or cold. You will probably be in the recovery room when you wake up. A nurse will monitor you. You may need medicines to reduce nausea or pain.

If you are staying in hospital, you will be transferred to a ward once you are fully awake.

You can go home after day surgery when you are:

  • fully conscious, alert and mobile
  • able to manage any side effects
  • drinking fluids
  • able to urinate (wee)

You can’t drive home after a general anaesthetic. You should arrange for someone to pick you up or help you get home. It’s best to be with someone for the next 24 hours so they can check on you.

What are the risks and side effects of a general anaesthetic?

Common side effects include:

Older people may have confusion and memory loss.

Other possible risks include:

In rare cases, patients may lose their sight, have a stroke or brain damage, or die.

Some people are frightened that they might be aware during the operation or feel pain. This is rare. Your anaesthetist will monitor you throughout the operation to make sure this is very unlikely to happen.

If you are worried about risks and side effects, talk to your anaesthetist before surgery.

Learn more here about the development and quality assurance of healthdirect content.

Last reviewed: July 2022

Back To Top

Need more information?

These trusted information partners have more on this topic.

Top results


Epidural is highly effective local anaesthetic procedure includes injecting anaesthetic around the spinal nerves in your lower back to block pain from contraction.

Read more on Pregnancy, Birth & Baby website

General anaesthetics - Better Health Channel

An anaesthetic is a drug or agent that produces a complete or partial loss of feeling.

Read more on Better Health Channel website

Anaesthesia and day surgery | Sydney Children's Hospitals Network

What is general anaesthesia? General anaesthesia is a way of making sure a child is more than just asleep

Read more on Sydney Children's Hospitals Network website

ANZCA | Anaesthesia for eye surgery

Eye surgery can be performed under eye block, topical anaesthesia or general anaesthesia.

Read more on ANZCA – Australian and New Zealand College of Anaesthetists website

ANZCA | Types of anaesthesia

There are several types of anaesthesia that may be used individually or in combination, depending on the surgery.

Read more on ANZCA – Australian and New Zealand College of Anaesthetists website

Anaesthesia and risk in infants | Sydney Children's Hospitals Network

Modern anaesthesia and surgery is very safe for children and infants

Read more on Sydney Children's Hospitals Network website

ANZCA | Anaesthesia and children

Anaesthesia is relatively safe and can be given to children of all ages, including newborn babies.

Read more on ANZCA – Australian and New Zealand College of Anaesthetists website

ANZCA | Anaesthesia and cosmetic surgery

This information has been developed by accredited specialist anaesthetists to help anyone who is considering cosmetic surgery in Australia or New Zealand. It will help you to understand the risks associated with anaesthesia, and the key questions you should ask before having a cosmetic procedure.

Read more on ANZCA – Australian and New Zealand College of Anaesthetists website

ANZCA | About anaesthesia

Most of us will need the care of an anaesthetist at some stage in our lives. We've created this information to help you feel more relaxed about having surgery under anaesthesia.

Read more on ANZCA – Australian and New Zealand College of Anaesthetists website

ANZCA | Anaesthesia for joint surgery

Joint replacement surgery is a common and effective procedure for relieving disability due to severe joint pain and loss of function.

Read more on ANZCA – Australian and New Zealand College of Anaesthetists website

Healthdirect 24hr 7 days a week hotline

24 hour health advice you can count on

1800 022 222

Government Accredited with over 140 information partners

We are a government-funded service, providing quality, approved health information and advice

Australian Government, health department logo ACT Government logo New South Wales government, health department logo Northen Territory Government logo Queensland Government logo Government of South Australia, health department logo Tasmanian government logo Victorian government logo Government of Western Australia, health department logo

Healthdirect Australia acknowledges the Traditional Owners of Country throughout Australia and their continuing connection to land, sea and community. We pay our respects to the Traditional Owners and to Elders both past and present.