Relevance of animal experiments to humans

The best evidence of an adverse human health effect is a properly conducted epidemiological study. But human beings should not be the sole test animal. Properly conducted animal studies have been shown to be preductive for carcinogenicity and toxicologic responses in human populations. We need to develop more efficient predictive animal tests for all the common serious toxic effects caused by chemicals. One particularly important use of epidemiological studies is to validate (or invalidate) the laboratory animal experiments. There is no more powerful tool than the combination of well conducted animal experiments and well conducted epidemiological experiments.