Replacement, Reduction & Refinement (3 Rs)
Replacement: For some biomedical research projects, animals may be replaced, either by methods that don’t involve animals at all (absolute replacement) or by those that use only the cells or tissues of animals (relative replacement). Many replacement alternatives involve these in vitro techniques where the studies are done with cells or tissues in culture.
Reduction: Some important kinds of testing just can’t be done without animals, at least at this time. In these cases, researchers still can work to reduce the number of animals used in a given study. With careful experimental design and sophisticated statistical techniques, it is often possible to use far fewer animals and still get valid results.
Refinement: Finally, for those animals that do undergo testing, scientists may refine their methods to lessen or eliminate pain, distress, or suffering and to make the animals more comfortable.