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Anaesthetic, local

Page last reviewed: 13/07/2011

Local anaesthetic is a type of painkilling medication that is used during some surgical procedures to numb the area of the body that is receiving treatment.

The word 'anaesthetic' comes from the Greek word meaning the absence or loss of sensation.

How does local anaesthetic work?

Local anaesthetic causes a complete loss of feeling to a specific area of your body without making you lose consciousness. It works by blocking the nerves from the affected part of your body so that pain signals cannot reach your brain. Therefore, you will not be able to feel any pain during the procedure.

When is local anaesthetic used?

Local anaesthetic is often used by dentists, surgeons and GPs when performing minor operations on small areas of the body. For example, local anaesthetic is often used during:

  • the removal or filling of teeth
  • minor skin surgery, such as the removal of moles, warts and verrucas
  • some types of eye surgery, such as the removal of cataracts (cloudy areas in the lens of the eye)
  • some types of biopsies, such as a needle biopsy, where a tissue sample is removed for examination under a microscope

Local anaesthetic is also sometimes used during more major surgical procedures, such as certain types of brain surgery.

For example, it may be used when a brain tumour is located in the area of the brain that controls speech. In such cases, as the tumour is being removed, you will need to remain conscious in order to respond to the surgeon's instructions. This helps them to ensure that your speech is harmed as little as possible during the procedure.

Some over-the-counter (OTC) creams and ointments contain local anaesthetic. For example, gels for mouth ulcers sometimes contain small amounts of benzocaine, which numbs the area around the ulcer.

Epidural anaesthetic

Sometimes, an epidural anaesthetic is used during childbirth to ease the pain of labour. An epidural is a type of local anaesthetic that works by blocking the nerve roots from the spinal cord. The anaesthetic is injected into the area below the spinal cord and numbs the lower part of the body, so that the woman does not experience pain while giving birth.


Anaesthetic is a drug used to either numb a part of the body (local) or to put a patient to sleep (general) during surgery.


The brain controls thought, memory and emotion. It sends messages to the body controlling movement, speech and senses.


Numbness refers to a lack of sensation in a part of the body.


Pain is an unpleasant physical or emotional feeling that your body produces as a warning sign that it has been damaged.


An ulcer is a sore break in the skin or on the inside lining of the body.


Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.

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