Anaesthesia uses different combinations of medications to keep a person calm and free of pain during surgery or other procedures. Depending on the purpose and type of anaesthesia, the composition may include medications to keep a person asleep, minimise pain, reduce anxiety, relax muscles or numb a specific area of the body.

General, regional and local anaesthesia are the three types of anaesthesia. General anaesthesia acts on the entire body and keeps a person asleep during a procedure. Regional anaesthesia numbs a large area of the body, such as below the waist or an entire limb. Local anaesthesia numbs a small area of the body, such as a patch of skin.

Depending on the type of anaesthesia, minor and temporary side effects may be seen, such as:
• Nausea
• Sore throat
• Headache
• Confusion
• Chills
• Sleep problems
• Trouble urinating
• Injection site pain
Complications are rare but include allergic reaction to the drugs, damage to mouth or teeth, heart attack, breathing problems, waking up during surgery, nerve damage and death.

In general anaesthesia, a person loses consciousness and the ability to move, form memories and feel pain. Most people describe the period as a blank, with no memory of what transpired. In local or regional anaesthesia, the person feels numb only in the area where the anaesthetic is injected. If a sedative is also given, the person may feel relaxed and drowsy during the procedure.

Certain medications used for general anaesthesia make people fall into a deep sleep, so that they do not move or feel pain during the surgery. They will be unaware of the surgery and will have no memory of the procedure when they wake up.