Piled evidence has demonstrated that non-coding RNAs (ncRNAs) play an important role in mediating the inter-individual variability observed in drug metabolism through the modulation of genes encoding drug metabolizing enzymes and transporters (DMETs) in addition to nuclear receptors. In contrast to the mechanism by which endogenous ncRNAs impact gene expression, synthetic interfering RNA (siRNA) has become rapidly under investigation as a therapeutic strategy to inhibit the translation of messenger RNA in an effort to treat human diseases. This symposium will provide a blended overview of recent research pertaining to ncRNAs and exogenous oligonucleotides within the context of drug metabolism and gene silencing, respectively.