LD50 Lethal Dose Testing

LD50 lethal dose testing is the most quantitatively controversial method, killing 50% of test animals to determine toxicity. Since 1927, millions of rodents died annually before OECD reforms in 2000s cut numbers by 75%. This test is 20% more efficient than #2 Draize for regulatory data, yet kills 100% of subjects at high doses. The fixed-dose procedure now reduces animal deaths by 40% compared to traditional protocols, aligning with modern ethics. Compared to Harlow's #1 psychological focus, LD50 is data-led but without emotional weight; 65% of toxicologists still defend its necessity, while opponents cite 30% error rates in extrapolating to humans.