At least three kinds of evolutionary applications are transforming medicine and public health. First are well-established population genetic and phylogenetic evolutionary methods that are now being used on new genetic data. Second are attempts to address evolutionary questions about why natural selection left our bodies vulnerable. Some of the most powerful applications are in infectious disease, not just antibiotic resistance but evolutionary models that show how vaccines can shape pathogens to make them worse killers. Thirdly, Darwins discovery means that our fundamental metaphor for the body has been incorrect. Thinking about the body as if it is a machine designed by an engineer conceals the reality of a body shaped by natural selection, vastly better than any machine can be in many respects, but hopelessly flawed in other ways that no engineer would tolerate for a minute. These insights are changing medical research and they will improve human health.