The human body, with 3.0 × 1013 cells and more than 3.8 × 1013 microorganisms, has nearly a one‐to‐one ratio of resident microbes to human cells. Initiatives like the Human Microbiome Project, American Gut, and Flemish Gut have identified associations between microbial taxa and human health. The study of interactions between microbiome and pharmaceutical agents, i.e., pharmacomicrobiomics, has revealed an instrumental role of the microbiome in modulating drug response that alters the therapeutic outcomes. In this review, we present our current comprehension of the relationship of the microbiome, host biology, and pharmaceutical agents such as cardiovascular drugs, analgesics, and chemotherapeutic agents to human disease and treatment outcomes. We also discuss the significance of studying diet–gene–drug interactions and further address the key challenges associated with pharmacomicrobiomics. Finally, we examine proposed models employing systems biology for the application of pharmacomicrobiomics and other ‐omics data, and provide approaches to elucidate microbiome–drug interactions to improve future translation to personalized medicine.