[Validity of alternatives to animal experimentation in biomedical research]

The "Three Rs" definition of alternatives by Russel and Burch (1959) refers to all methods, protocols, or technologies which replace the use of animals altogether, reduce the number of animals required, or refine existing procedures or technologies so as to minimize the level of stress endured by the animal. The move towards alternative methods in biomedical research must be seen as a gradual and evolutionary process during which each candidate method must be considered in a sequence of three consecutive steps, i.e., development of the test protocol, validation of its scientific merits and evaluation of its applicability to problems arising in practice. The validity of alternative methods is discussed in relation to the new legislation on animal experimentation and validation schemes already published.