Humane endpoints are predetermined criteria for terminating experiments before animals reach severe suffering, and their consistent application is one of the most impactful welfare improvements in laboratory animal research.
The adoption of humane endpoints represents a fundamental welfare improvement that can be implemented within existing research frameworks without requiring new technologies or large expense. The historical practice of using death as an experimental endpoint subjected animals to extended periods of severe suffering that generated no additional scientific value beyond data obtainable at earlier time points. Implementing scoring systems that trigger euthanasia when clinical condition reaches predetermined thresholds requires researcher training, clear protocols, and institutional commitment to welfare over convention. Resistance to humane endpoints sometimes reflects concerns about data comparability with historical studies or perceived scientific value of endpoint data. These concerns have generally not been supported when rigorously tested. The welfare benefit of consistent humane endpoint application across the millions of animals used in research globally would be substantial.