We aren't completely sure that animals are biologically close enough to humans to completely give us a good idea of how humans will react to certain chemicals and medicines, but that is still better than exposing people to unknown risks. In the past, poor people, especially poor minorities or prisoners were subjected to all kids of medical experiments without consent and without knowing the risks. Animal testing is a step better than that.
Animal testing isn't ideal, as the example shows, but there's no denying that it has had some positive effects on our society. If there are better methods for testing, we should definitely use them, and also there are ethical issues with testing animals. However, it seems to be at least somewhat effective.
The benefits of testing on animals permeates the annals of science. Humans need the knowledge to find the proper medicines to keep us healthy or safe from harm. Sorry folks, but the cute little mice will have to be tested upon. Better my health than theirs in the long run
It is generally agreed upon that a human life is more valuable than an animal. Testing on animals may not be perfect, but it can save a human life. Animals and humans are physiologically different but enough similarities exist to make it so that testing on an animal can give useful information to make a product safe for people.