The 3Rs: replacement, reduction and refinement

The '3Rs' is a basic philosophy of animal ethics and refers to the principles of replacement, reduction, and refinement.

In accordance with the Australian code for the care and use of animals for scientific purposes, when assessing proposals to use animals for scientific purposes, animal ethics committees will require evidence that the investigator or teacher has considered the replacement, reduction and refinement of animal use in their proposal and will continue this process throughout the life of the project.


Replacement involves using methods that permit a given purpose of an activity or project to be achieved without the use of animals.

Investigators and teachers must replace the use of animals with non-animal alternatives wherever possible. For example using in-vitro culture to produce antibodies or a plastic model to illustrate anatomy.


Investigators and teachers must consider whether it is possible to reduce the number of animals being used without compromising the scientific or statistical validity of the outcomes of the project. When implementing reduction, they must ensure that reduction is not at the expense of greater suffering of individual animals.

The use of animals must not be repeated within a project or between projects unless such repetition is essential for the purposes of the project. Teaching activities must use no more animals than the number required to meet the educational objective.

Animals bred for scientific purposes must be managed to avoid or minimise the production of excess animals.

An example of reduction would be using abattoir organs to practise artificial insemination before training on live animals.


Refinement involves using methods that alleviate or minimise potential pain and distress and enhance animal wellbeing.

There are many options for refinement specific to each type of animal use. Within the justified limitations of the activity's purpose and requirements in the use of animals, refinement includes:

  • selecting animals that are suitable for the activity
  • designing and managing animal facilities to meet species-specific and project requirements
  • transporting and handling animals under conditions that meet their behavioural and biological needs
  • not taking wild animals from natural habitats if captive-bred animals are available and suitable
  • ensuring the best available scientific, statistical and educational techniques are used by competent people or under the direct supervision of competent people
  • avoiding or minimising pain and distress, and promptly relieving pain and distress not predicted (in the proposal if not approved by the animal ethics committee) in preference to completing the project
  • management of pain and distress appropriate to the species. Tranquilisation analgesia and anaesthesia must be used for procedures that would normally involve tranquilisation analgesia and anaesthesia in current medical or veterinary practice
  • ensuring the planned end point of projects is as early as possible and minimise the duration of animal use. Death as an endpoint must be avoided whenever possible.

Also consider...