Three Rs principle (in animal experimentation)

The Three Rs principle was launched in the early 1960s by two English biologists, Russel and Burch in their book “The Principle of Humane Experimental Technique”. The 3 Rs stand for Replacement, Reduction and Refinement.

Replacement alternatives refer to methods which avoid or replace the use of animals. This includes both absolute replacements (i.e. replacing animals by computer models) and relative replacements (i.e. replacing vertebrates, with animals having a lower potential for pain perception, such as some invertebrates).

Reduction alternatives refer to any strategy that will result in fewer animals being used to obtain sufficient data to answer the research question, or in maximizing the information obtained per animal and thus potentially limiting or avoiding the subsequent use of additional animals, without compromising animal welfare.

Refinement alternatives refer to the modification of husbandry or experimental procedures to minimize pain and distress, and to enhance the welfare of an animal used in science from the time it is born until its death.

Source: GreenFacts based on the Canadian Council on Animal Care, Three Rs introduction 

Deutsch: Drei R – Prinzip (im Bereich der Tierversuche)
Español: Principio de las tres erres (en la experimentación animal)
Français: Principe des trois R (dans l'expérimentation animale)