Some toxicity tests consume hundreds or thousands of animals per substance examined (e.g., lifetime cancer studies consume approximately 400 rats and 400 mice; a study of birth defects and developmental toxicity consumes 1,300 rats and/or 900 rabbits; and a study of sexual fertility and reproduction generally consumes 200 litters of rodent pups—or upwards of 2,600 animals) [1].

Moreover, some countries’ statistics on animal use indicate that toxicity testing accounts for up to 80% of the most painful procedures to which animals are subject for all experimental purposes (e.g., death as the endpoint in acute systemic toxicity studies) [2].

These concerns are exacerbated by the fact that some regulations prescribe dozens of separate animal tests to evaluate the full range of potential toxicities for a single substance (e.g., upwards of 12,000 animals may be consumed to test a single pesticide chemical according to U.S. regulations).

¹OECD [Organisation for Economic Co-operation and Development]. OECD Guidelines for the Testing of Chemicals. Paris: OECD (2008).

²CCAC [Canadian Council on Animal Care]. Facts & Figures – CCAC Animal Use Survey: Number of Animals Used in 2006 per Purpose of Animal Use and Category of Invasiveness. Ottawa: CCAC (2008).