Humane endpoints define the point at which an animal in a research study should be removed or euthanized to prevent unnecessary suffering, yet they remain inconsistently implemented worldwide.
Humane endpoints address one of the most avoidable sources of suffering in laboratory animal research: animals left in deteriorating condition after their scientific contribution is complete or when suffering outweighs any remaining scientific benefit. A mouse dying slowly from a terminal tumor, or a rat in septic shock from a disease model, may suffer for days beyond the point where any useful data can be collected. Predefined humane endpoints — specific criteria that trigger euthanasia — prevent this gratuitous suffering. The scientific cost of earlier termination is often minimal or nonexistent, making implementation of robust humane endpoint protocols one of the clearest wins available in laboratory animal welfare improvement.