Every individual bears, on average, approximately 18,000 variants in their 231 pharmacogenes that can only be identified by NGS technologies, most of which are rare variants that may occasionally lead to rare drug outcomes. Notably, apart from the interindividual differences observed in the pharmacogenes, there are remarkable interethnic differences in the prevalence, that is, allele frequencies of pharmacogenes that have been reported in various studies. These differences are of fundamental importance not only to prescribe tailor-made theranostics, with direct impact on public health, but also to empower drug discovery. In other words, it is of utmost importance that we gradually shift from personalized to ‘populationalized’ medicine with the prospect of enjoying numerous tangible benefits not only for individual patients but also for the entire healthcare system and society as a whole. At the same time, genome-guided clinical trials can help toward reducing the immense drug development cost and the overall length of clinical trials that a drug may need to find its way to the market.