It is common to argue that animal experimentation is justified by its essential contribution to the advancement of medical science. But note that this argument actually contains two premises: an empirical claim that animal experimentation is essential to the advancement of medical science and an ethical claim that if research is essential to the advancement of medical science, then it is justified. Both claims are open to challenge, but in the logic of the case, only one of them needs to be shown false or moot in order to refute the argument. I argue that the ethical claim does not withstand scrutiny. In addition, the main so-called “alternatives” to animal research do not merit that label since they still involve the use of nonhuman animals.