Twenty-five centuries after Hippocrates, we are at the beginning of an era of individualized, molecular, and genomic medicine, where diagnosis, prognosis, and treatment will be increasingly based on our understanding of the human organism's genetic and molecular composition. The most difficult task in this process has proven to be the application of the scientific advancements to the clinical setting, and clinical pharmacology is an essential discipline in this translational process. This article traces the roots of the emerging personalized and genome-based medicine to the teachings of Hippocrates.