'The Gut Microbiome, Pharmacology, and Nutrition'The microbes residing in and on the human body influence host health and disease in part due to their metabolism of xenobiotics (foreign compounds like host-targeted drugs, antibiotics, and dietary components). Yet microbial xenobiotic metabolism remains an underexplored aspect of pharmacology and nutrition, with the bacterial groups and metabolic pathways responsible often unknown. We are addressing this critical knowledge gap through the use of methods for the single cell analysis of gut microbial communities, metagenomic sequencing of microbial community DNA and RNA, and gnotobiotics (germ-free and colonized mice). Ultimately, we aim to obtain a more comprehensive view of human metabolism, yielding fundamental insights into host-microbial interactions and supporting translational efforts to predict and manipulate the metabolic activities of our resident gut microbes.