Animals are used in biomedical research to study disease, develop new medicines, and test them for safety. As the Oxford Centre for Animal Ethics' review Normalising the Unthinkable acknowledges, many great strides in medicine have involved animals. However, their contribution has not always been positive. Decades of attempts to develop treatments for diseases including asthma, cancer, stroke, and Alzheimer's using animals have failed to translate to humans, leaving patients with inadequate treatments or without treatments at all. As Normalising the Unthinkable points out, we have to confront the fact that animal research may have hindered progress, at least in some respects. For example, animal tests have been shown to have very little ability to predict the safety of medicines for human patients. A dramatic illustration of this failing is TGN1412, which almost killed 6 clinical trial volunteers in 2006, after crab-eating macaques showed the drug to be safe, even at massive doses. This failing contributes to adverse drug reactions, which are now one of the world's leading causes of death, killing hundreds of thousands of people every year and hospitalizing millions. A revolution in science and technology has produced a new generation of more relevant and predictive tools, which could be used to create safer medicines more quickly and at less cost: a win-win situation that should be supported by everyone. The obstacle preventing this from happening is governments' continued insistence on animal testing. Yet the evidence is clear that reliance on animals as surrogate humans puts patients at risk, can delay medical progress, and can cause effective treatments to be wrongly discarded. There is a compelling case to be made that animal research is an ethical issue for humans as well as for animals.