Welfare of Animals Used in Toxicology Testing

Toxicology testing uses animals to assess the safety of chemicals, pharmaceuticals, food additives, and environmental contaminants, involving a wide range of procedures with varying welfare impacts.

Key Facts

The OECD publishes standardised toxicology test guidelines used globally for chemical safety assessment
Lethal dose 50 (LD50) tests, historically requiring death of 50% of test animals, have been largely replaced by acute toxic class and limit dose methods
Repeated dose toxicology studies exposing animals to chemicals for 90 days or longer involve significant cumulative welfare harm
The EU REACH regulation requires extensive chemical safety data that historically relied heavily on animal testing
Validated alternative methods including 3D cell culture models, organ-on-chip systems, and computational toxicology are being adopted for some endpoints
Read-across and chemical structure-activity relationship modelling can predict toxicity without animal testing for some chemical classes

Welfare Considerations

Toxicology animal testing spans the full welfare spectrum from minimally invasive acute tests to long-duration repeated dose studies that cause sustained suffering. Regulatory modernisation driven by the EU REACH regulation has created both the demand for alternative methods and the investment to develop them. The most welfare-impactful near-term changes are: elimination of still-used LD50 variants, adoption of validated alternatives for acute endpoints, and genuine regulatory acceptance of non-animal methods for repeated dose toxicology where validation is available. Sustained regulatory reform rather than voluntary commitments is required to drive systematic welfare improvement.

What You Can Do

Support regulatory reform that accepts validated non-animal toxicology methods
Advocate for OECD test guideline updates that adopt validated alternatives
Engage with consumer product companies about their chemical safety testing policies
Support NC3Rs and equivalent bodies funding toxicology alternative development
Learn about the regulatory barriers that currently maintain animal testing despite available alternatives