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NC3Rs | 20 Years: Pioneering Better Science

3Rs for the public

Many scientists who use animals in their research are committed to finding alternatives and ensuring high standards of animal welfare, but there is always more that can be done.
Two scientists look into microscopes

The NC3Rs was set up to help scientists replace their use of animals and, where this is not possible, reduce the number of animals used and refine the care of the animals to keep pain and suffering to a minimum. There are many ways to achieve these aims, which are known collectively as the 3Rs.

In the UK, animal research that can cause pain or suffering is regulated by the Animals (Scientific Procedures) Act 1986 with the Home Office as the lead government department. The law permits the use of animals in research as long as there is no alternative. Where their use is unavoidable, it requires that scientists only use the minimum number of animals and take steps to limit any pain, suffering or distress.

What are the 3Rs?

The principles of the 3Rs were first proposed in 1959 and stand for:


Avoiding or replacing animal use e.g. using cell cultures, computer modelling, or human tissue or volunteers.


Where animal use is necessary, keeping numbers to the minimum e.g. using statistical methods to determine the smallest number of animals that can be used in an experiment.


Where animal use is necessary, minimising pain and suffering and improving welfare e.g. using pain relief and providing housing that allows animals to perform their natural behaviours.

We have produced a short video introducing the 3Rs and their scientific importance. This was designed for training scientists, technicians and students, but is useful for anyone interested in learning more about animal research, the 3Rs and the work we do. It includes case studies relating to each of the 3Rs from researchers whose work we have funded.

What does the NC3Rs do?

 The NC3Rs is an independent UK-based scientific organisation dedicated to the 3Rs. We were set up in 2004 in response to the House of Lords Select Committee report on Animals in Scientific Procedures, which recommended the establishment of a national centre to help advance the 3Rs.

We work with scientists and organisations from across the life sciences sector, including universities, industry and regulatory authorities, both in the UK and internationally. As well as funding scientific research into the 3Rs, we support the development of 3Rs technologies and drive changes in policy, regulation and practice. We engage with the scientific community through collaborating on research projects, running events and producing guidelines and other resources, including our website. Find out more about who we are and what we do.

Learn more

While much of our work is aimed at scientists, you can find articles, videos, podcasts and other resources aimed at a more general audience that have been produced by NC3Rs, the researchers we fund and other organisations in the links below.

Research round-ups

Discover how the 3Rs are embedded in research and the science driven by 3Rs tools, technologies and approaches, in this series of articles written for a general audience.

Explore 3Rs methods and technologies on the NC3Rs F1000 Gateway – an open access platform for our grant holders to maximise the 3Rs impact of their work.

The NC3Rs F1000 Gateway homepage.

Find out about the work we have funded to build the evidence base for refining the use of fish in research.

A group of zebrafish swimming in a tank.


An introduction to organ-on-a-chip technology and its potential to replace animal studies, aimed at 14 to 19 year olds and available in English and Spanish.

Organ on a chip technology

Our citizen science project with MRC Harwell invited the public to get involved in improving laboratory mouse welfare by watching and labelling videos of mice in their home cages.

A cartoon of three mice. The mouse on the left is wearing a green top and eating, the mouse in the centre is wearing a red top and grooming itself, and the mouse on the right is wearing a blue top and drinking water.

Videos and podcasts

Learn more about ESTIV's in3 Project, which aims to create lab- and computer-based tools for assessing the safety of chemicals.

A screenshot from the linked video representing in vitro and in silico methods

Other resources