Practices of testing drugs and trying cures were clearly central to premodern medicine. As the present articles demonstrate, a wide range of actors conducted a variety of practices in order to assess drug efficacy; determine the virtues of plants, animals, and minerals; ascertain the composition of compound drugs; tweak production and application methods; and much more. Some of this testing occurred at familiar locales, such as the German courts and the Paris Academy of Sciences, but other examples took place at less studied locations, such as French hospitals, Italian apothecaries' shops, and Dutch universities. Together they illustrate the centrality of drugs and cures to many physicians' interests, the traditional focus on diet and regimen notwithstanding. They also reveal the extent to which questions about experiments, proof, and efficacy that famously infused discussions in the later seventeenth century had preoccupied practitioners as far back as the fourteenth century. The snakestone experiments discussed in the introduction had many precursors. Over the five hundred years surveyed in this volume, experiential thinking continuously played a crucial role in learned assessments of medicines and drugs. Drug testing was, from the time of Galen, structured and evidence-based with an aim to produce transferable results. As such, we argue that it is time to include medicine and, in particular, drug testing into our histories of experimentation. By doing so, we gain further insight into changes and continuities of experimental practices across premodern Europe. Rather than focusing on "experiment" as a definitive and monolithic practice that had an obvious origin, these essays demonstrate multiple strains of "experimental thinking" in various contexts.