Louis Caplan, MD, Harvard Medical School, Boston, MA, talks about the differences between precision medicine and personalized medicine. He defines the term ‘precision’ as being meticulous and accurate, whereas ‘personalized’ relates to an individual. Both approaches must be integrated together in medicine. Prof. Caplan emphasizes the importance of medicine incorporating a highly personalized approach, taking into account the differences between each individual. Prof. Caplan explains how clinical diagnostics and treatment in stroke has advanced with technology such as neuroimaging, vascular studies, cardiac studies, and blood studies. Prof. Caplan explains the downsides of clinical trials studying interventions in large heterogenous groups and believes a more personalized, theoretical approach is also important. This interview took place during the European Academy of Neurology 2021 congress.