An introduction to the 3Rs

Definition of the 3Rs

The “3Rs” principles of “replacement, reduction and refinement” of laboratory animal use were first proposed by William Russell and Rex Burch in their book ‘Principles of Humane Experimental Technique’, published in 1959. Application of the principles should aim to reduce the adverse effects caused to animals, improve animal welfare and enhance the quality of the science in which the animals are used. These three principles are now widely recognised and are requirements of UK and European laws on the use of laboratory animals. Indeed, their implementation is part of the standard conditions of both the personal and project licences.