No, it's not necessary. It's not only unnecessary but also misleading, because animals have very different ways of processing drugs and toxins than humans do. First of all, 90% of tests done on animals are tests that ARE BEING DONE FOR DRUGS AND CHEMICALS THAT HAVE ALREADY BEEN TESTED ON ANIMALS AND TURNED DOWN BY THE FDA. And there are SO many other ways to test the effects of those things than to test on animals which, by the way, isn't always a good thing, because animals have completely different systems than we do. For example, it took DECADES for birth control to come out on the market, because they tested on animals and it didn't work for them at all; they still got pregnant. Same with Tylenol, which is perfectly harmless to humans, but if a dog had even a small dose, it would die. Testing on animals is unnecessary, cruel, inhuman and painful.