Use and misuse of an imprecise concept: alternative methods in animal experiments.

The concept of inhumanity of Russell & Burch in 1959 with proposals for human procedures in experiments on animals by way of replacement, reduction and refinement (the 3 R's) and the revival of these by Smyth (1978) as alternatives to animal experiments are presented. Since then under the name 'alternative methods', replacement of in vivo by in vitro methods has found great public attention and promotion. It is argued that alternative methods are a fallacy, because in the progress of research a continual control and reinvestigation of findings on each system level is required until knowledge is complete, which makes in vivo experiments irreplaceable. True alternatives exist only for refinement within a system level. On the level of the organism, refinement would be in the care of animals and experimental procedure through alleviation of stress. The possibilities which refinement offers for animal welfare have been nearly forgotten and need promotion among researchers, animal technicians and attendants.