The ability to make pluripotent stem cells from adult somatic cells has revolutionized cell biology, especially as access to differentiated tissues from induced pluripotent stem cells has improved. Differentiated cells from induced pluripotent cells are more similar to intact tissue than cell lines or primary culture and rodents thus have begun to change the standard models to more human in vitro-based models. In this talk, I will highlight the numerous examples where stem cell-derived tissues have replaced, refined, and/or reduced the reliance on animal models in drug screening, toxicology, and product safety.