Do Medical Experiments on Animals Really Yield Meaningful Results?


As long as men have experimented upon animals to gain knowledge of physiology or pathology there have been others who have decried the practice. Among them was Doctor Johnson, who said of vivisection that “if the knowledge of physiology has been somewhat increased [by it], he surely buys knowledge dear, who learns the use of lacteals at the expense of his humanity.”

Doctor Johnson argued that the cure of not a single medical condition had been discovered by the use of animal experimentation, and even if that is no longer the case there are nevertheless those who maintain that the benefits of animal research are small by comparison with their cost in the suffering of sentient beings that such research entails.

Two authors in a recent edition of the British Medical Journal, one of them an eminent epidemiologist and the other a sociologist, attempt to answer the question of whether or not animal research is a boon to medicine. Their conclusion is that it is much less so than is commonly supposed, and in some cases it is actually harmful. Since the only possible moral defense of vivisection is that it promotes medical advance, it should be stopped if it does not.

The authors point out that, according to a survey of medical scientists who perform animal experimentation, more are motivated by a desire to advance knowledge or careers than by a desire to help suffering humanity, and are actually rather indifferent to the practical use or otherwise of their work.

This is perhaps just as well, at least for their own peace of mind, because the practical value to patients of most animal experimentation is nil. This is for more than one reason.


First, the quality of much animal research is low. It suffers in spades from all the defects of much clinical research, at least until very recently. Experiments on animals are rarely well-controlled and even when they are, they are rarely double blind: that is to say, the experimenter and the recorder of the results is one and the same person, a conflict of interest that leads inevitably to readings of results biased in favor of the experimenter’s hypothesis.

Then there is publication bias: positive results are reported much more frequently than negative ones, giving a misleading impression of their significance and importance. And this in turn may lead to unnecessary and harmful experiments on human beings. Substances which have been tried with apparent success on animals very rarely work in humans.

But even if the defects in animal research could be overcome, there would still be no guarantee that they would be of utility to human medicine, for the rather obvious reason that the biology of humans is different from that of rats, rabbits and gorillas. This difference is currently irreducible, and even transgenic animals, that is to say animals with one or more human genes inserted into them, have proved to be unreliable biological models.

The authors do not claim that animal experimentation is never successful in developing new drugs or procedures; but they say that so much experimentation of that kind is now done that some success must be expected merely by statistical chance.

The article concludes:

Poorly designed [animal] studies… may result in expensive but ultimately fruitless clinical trials that needlessly expose humans to potentially harmful drugs… Moreover, if poorly conducted studies produce unreliable findings, any suffering endured by animals loses its moral justification because their use cannot possibly contribute towards clinical benefit.

I have a suspicion that things are much more complex than this allows; and that it is not quite so easy to discern what work has been useful and what useless. I also ask whether, from the animals’ point of view, it is better to have existed and been experimented upon than never to have existed at all.


shutterstock /  anyaivanova /  Rob Hainer