The 3Rs

Humane animal research should follow the principles of Replacement, Reduction, & Refinement (the 3Rs). These principles were laid out 60 years ago in the book The Principles of Humane Experimental Techniques by William Russell and Rex Birch. The 3Rs are internationally accepted principles for the ethical consideration of animals in research. They are often key goals for organizations and regulatory bodies that conduct animal research. Furthermore, public attitudes towards animal research are more positive when the 3Rs are used. Are you a member of the public curious about the 3Rs? Check out this webpage.

The NA3RsC has an initiative working to create a 3Rs certificate program for anyone working with animals in the field. Stay tuned for this exciting initiative.



Methods that minimize pain, suffering, and distress of research animals as well as improving their welfare. For example, providing housing that allows the expression of species-specific behaviors, modifying handling methods, and training animals to cooperate with handling. NA3RsC has an initiative focused on Refinement.


Methods that minimize the numbers of animals required per experiment or study designs to achieve robust results. Can also include methods that maximize the amount of information gathered per animal in an experiment. Sharing data and resources between research groups can also contribute to reduction so that multiple groups can look at the same data to different ends. NA3RsC has an initiative focused on Translational Digital Biomarkers.


Methods or technologies which avoid, or replace, the use of animals. Partial or relative replacement refers to replacing animals with animals that are not considered capable of experiencing pain/distress such as invertebrates like Drosophila, nematode worms, and social amoebae, and immature forms of vertebrates. Partial replacement also includes using cells or tissues from animals killed solely for this purpose. Full replacement refers to replacing living animals with non-animal methods. For example, NA3RsC has initiatives focused on Environmental Monitoring and Microphysiological Systems.

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