Document Type


Publication Date



Imagine a test in which up to 100 animals are forced to consume a toxic substance in an amount high enough to kill half of them. Then imagine that the explicit purpose of the test is to kill those animals. Incredibly, such a test not only exists but each year also claims the lives of from two to four million animals.

The test is the lethal dose 50, or LD50 as it's commonly called. Its purpose is to measure the toxicity of a substance by determining how much of that substance will kill half of a group of some 60-100 test animals in a specific amount of time.

The HSUS believes that inducing untold suffering in animals in order to provide questionable data can no longer be tolerated. Here in Washington, D.C., we are spearheading a drive supported by hundreds of animal-welfare groups across the country to force the federal government to call a halt to this unconscionable activity.