The home page of PharmGKB provides a straightforward schema for understanding pharmacogenomics. After drugs are delivered, PKs and PDs both involve sets of genes and lead to both efficacious and toxic effects. Variation in response can be related to the PK and PD genes by studying their variations in the human population. All data in the PharmGKB are indexed as being relevant to PK, PD, clinical outcomes (CO), genetic variation (GN), or functional assays at the molecular and cellular level (FN).