The Three Rs — Replace, Reduce, and Refine — provide the ethical framework for laboratory animal welfare globally. Understanding and applying these principles minimises suffering while enabling essential biomedical research.
Laboratory animals experience welfare challenges including the pain and distress of experimental procedures, housing in barren environments, social isolation, and the stress of handling and transport. The Three Rs framework provides a systematic approach to minimising these harms. Refinement advances — improved anaesthesia, analgesia, humane endpoints, and environmental enrichment — have substantially improved welfare for animals that remain in research. However, implementation varies considerably between institutions and countries, and stronger regulatory oversight and independent welfare assessment remain important.