The PharmGKB is a pharmacogenomics knowledge resource that encompasses clinical information including dosing guidelines and drug labels, potentially clinically actionable gene-drug associations and genotype-phenotype relationships. PharmGKB collects and disseminates knowledge about the impact of human genetic variation on drug responses; curates and displays primary genotype and phenotype data; annotates gene variants and gene-drug-disease relationships via literature reviews; summarizes important pharmacogenomic genes and drug pathways; and enables consortia examining important questions in pharmacogenomics. PharmGKB is funded by NIH/NHGRI/NICHD (U24 HG010615).