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The 3Rs

The 3Rs represent the principles of Replacement, Reduction and Refinement, forming a compassionate framework for animal research. Their aim is to replace animals in scientific studies with alternative methods, such as computer modelling, and where animals remain necessary, to minimise pain or harm and to enhance their welfare.

These principles are the foundation of EU and national legislation concerning the protection and welfare of animals used in science, encompassing domestic as well as wild animals and birds involved in research projects. You can read more about these principles in the table below.

Principle	What it means	Examples
Replacement	Embracing alternative methods that do not involve live animals.	Utilisation of computer models, cell-based assays, videos, and invertebrates.
Reduction	Employing the most appropriate number of animals for the study.	Using good experimental design to ensure that neither too few nor too many animals are used. Leveraging new technologies such as imaging can also help, while sharing tissues between research groups is also beneficial.
Refinement	Minimising suffering and enhancing animal welfare in studies.	Ensuring careful animal handling by trained researchers, providing anaesthesia and pain relief during procedures, maintaining high standards of housing and husbandry, including access to toys and nesting material.

For further information on the 3Rs, see the pages below:

• Alternatives
• Rodents
• Fish
• Large mammal
• Other animals
• General 3Rs
• Useful 3Rs websites

See other useful links.

If you have any queries about these links, or suggestions for additional useful 3Rs resources that could be included here, please email sap@hpra.ie.