The term "pharmacometabolomics" was coined in 2006 to reflect the potential of the predrug metabolomic signature to predict the postdrug response. Metabolomics can be used to examine the contribution of nongenomic factors, such as the environment, diet, or the gut microbiome, to the overall drug response. As such, the complexity of human biology afforded by metabolomics can complement genomic approaches, ultimately moving the discipline of clinical pharmacology closer to full implementation of personalized medicine.