General toxicity testing: sense and non-sense, science and policy

The dramatic increase in the number and variety of industrial chemicals in addition to natural compounds, and the increased public concern about their health effects, has in the last few decades led to a remarkable development in number and types of toxicity tests employed to assess safety of chemicals. Not too many years ago, toxicity tests were relatively simple in design and conduct. They were sometimes inadequate in a number of aspects. Toxicity testing has now become an unbalanced mixture of sound science and policy. Many times companies wishing to market products internationally are faced with a plethora of different national regulatory requirements. In this presentation attention is given to requirements for toxicity data and the need for harmonization in guidelines while avoiding rigid protocols. The wisdom and necessity of conducting all currently required tests will be considered. The relevance of certain biochemical, hematological, and pathological parameters is discussed as is the relevance of Good Laboratory Regulation for toxicity testing. The importance of a scientific evaluation of all chemical biological data derived from modern sensibly designed toxicity tests with respect to extrapolation and safety assessment is emphasized. Future development in certain areas of toxicity research is stressed and examples are given.