The modern era of chemistry has resulted in dramatic improvements in the overall human condition. In addition to new pharmaceuticals, modern chemistry has brought with it enormous health and social benefits Introduction of chemistry-based technologies, however, has also been clearly associated with potential human health risks. The dramatic increase in pharmaceutical and chemical technologies in the post World War II era, coupled with associated examples of demonstrated human toxicity, led to development and application of an expanded and standardized battery of animal and other toxicity tests designed to characterize the potential hazards and risks associated with chemical exposures. This unit discusses the current approach to industrial chemical and pesticide toxicity testing.