“The first principle is that you can only use animals if they’re the most ethically acceptable way to address the question. It goes beyond the “replacement” part of the three Rs in that scientists must not just consider alternatives to using animals, they must prove that there are no viable alternatives. An IACUC [Institutional Animal Care and Use Committee], for example, might ask an investigator to detail the science showing that animal alternatives like organ on a chip or microdosing humans aren’t viable. It puts more teeth into replacement.
Another principle would ask scientists to detail how much humans and society are likely to benefit from the research, and contrast that with how much animals are likely to suffer. Even if the benefits of using animals outweigh the costs, we want researchers to think about how they can mitigate—and even eliminate—any harms caused to animals during their experiments. Are they drawing blood more than they need to? Are they handling rodents more often than necessary?
Scientists also should be thinking about how to give these creatures the best life possible in the lab. That could include making sure they have companions, exercise, and other stimulating activity.”
More on Is it time to replace one of the cornerstones of animal research? via Science.