The Pharmacogenomics Knowledgebase (PharmGKB) is a comprehensive resource that collects, curates, and disseminates information about the impact of human genetic variation on drug responses. It provides clinically relevant data, including dosing guidelines, annotated drug labels, and gene-drug associations. Curators assign levels of evidence to these associations based on well-defined criteria and literature review. The PharmGKB integrates primary pharmacogenetics and pharmacogenomics literature into gene variant annotations, drug-centered pathways, and VIP gene summaries. Clinical annotations combine multiple variant annotations into a single summary of variant-drug-phenotype associations, with each annotation linked to supporting PubMed identifiers. The level of evidence for each annotation is determined by criteria such as replication, P values, and odds ratios. The PharmGKB supports various clinically relevant projects, including data-sharing consortia and implementation initiatives like the Clinical Pharmacogenetics Implementation Consortium (CPIC), which provides drug-dosing guidelines based on individual genotypes. The PharmGKB is a critical resource for enabling clinicians and researchers to implement pharmacogenomic knowledge in personalized medicine.The Pharmacogenomics Knowledgebase (PharmGKB) is a comprehensive resource that collects, curates, and disseminates information about the impact of human genetic variation on drug responses. It provides clinically relevant data, including dosing guidelines, annotated drug labels, and gene-drug associations. Curators assign levels of evidence to these associations based on well-defined criteria and literature review. The PharmGKB integrates primary pharmacogenetics and pharmacogenomics literature into gene variant annotations, drug-centered pathways, and VIP gene summaries. Clinical annotations combine multiple variant annotations into a single summary of variant-drug-phenotype associations, with each annotation linked to supporting PubMed identifiers. The level of evidence for each annotation is determined by criteria such as replication, P values, and odds ratios. The PharmGKB supports various clinically relevant projects, including data-sharing consortia and implementation initiatives like the Clinical Pharmacogenetics Implementation Consortium (CPIC), which provides drug-dosing guidelines based on individual genotypes. The PharmGKB is a critical resource for enabling clinicians and researchers to implement pharmacogenomic knowledge in personalized medicine.