[What may be learnt from short- and long term tests and from studies on cancerogenicity, teratogenicity and...

During the last 15 years the transferability of results from animal experiments to humans has been improved so that today certainly more than 70% of possible side effects can be predicted. Systemic hypersensitivity reactions cannot be predicted, however, since to date there are no safe animal experimental methods available. In spite of many decades of research in the field of animal experimental cancerogenesis the value of investigations of this kind for humans can be limited by the selection of unsuitable animal species, use of inadequate modes of administration or excessive doses. Similar aspects apply to reproduction toxicology; there are many examples in cancerology and teratology for false-positive and -negative results from animal experiments. In chemomutagenesis comparisons of in vivo cytogenetic investigations in somatic cells of animals and humans have revealed largely concurring results. However, only stable mutations found in generative cells are signs of a genetic danger. It will therefore have to be clarified which conclusions for generative cells should be drawn from changes in somatic cells. Furthermore, the elaboration of methods for the determination of the mutation of genes in the organism of mammals still requires intensive research.