The principles of the 3Rs concerning animal experimentation have been postulated in 1959 by William Russell and Rex Burch in a book entitled “Principles of Humane Experimental Technique”. The principles are today internationally widely recognized by scientists as a moral obligation. They are moreover implemented in many national legislations on animal protection.
In short, the 3Rs stand for:
- Replace: Whenever it is possible to replace an animal experiment by an alternative method (e.g. an in vitro study, a study in humans, a computer simulation study, or a study using lower organisms), the animal experiment should not be pursued.
- Reduce: If an animal study is considered necessary, as few animals as possible should be foreseen, however not too few in order not to compromise the validity of the study.
- Refine: Before, during and after the experiment use approaches and methods to minimise the distress to the animal.
Whereas Replacement and Reduction have to be considered primarily in the planning phase of an experiment, Refinement has primarily to be implemented when handling the animal in practice.
Although the principles of the 3Rs are widely promoted, the scientific community is accepting the fact that there is room for improvement in the practical implementation of the principles.