Thalidomide and cigarettes have absolutely no effect whatsoever on rats. A small dose of paracetomol treats a headache in humans but a proportionally similar dose kills snakes. What is toxic/beneficial for one species is not necessarily so in another. There are also now alternative methods which are actually much more efficient, more effective, cheaper and cruelty-free (tissue cultures, mathematical models, etc.). And scientifically convalidated. Tests on animals cannot be convalidated, which is why there are risks for use in humans. With rare exceptions, the results of animal tests in the past are unreliable, unrepeatable and downright misleading (negative results never get published...) Most modern scientists agree that the insistence on animal tests is actually slowing down progress. 300 million rabbits alone died in tests in Europe last year.
My point is that our attitude to animals is part and parcel of our overall attitude to the Creation: the miracle of this planet and all its forms of life is being poisoned, polluted, debased in the name of profit. It's immensely sad to think that billions of years will be utterly wiped out in the space of 3 or 4 centuries.