Ferulic acid(FA) is an active component of herbal medicines. One of the best documented activities of FA is its antioxidant property. Moreover, FA exerts antiallergic, anti-inflammatory, and hepatoprotective effects. However, the metabolic pathways of FA in humans remain unclear. To identify whether human CYP or UGT enzymes are involved in the metabolism of FA, reaction phenotyping of FA was conducted using major CYP-selective chemical inhibitors together with individual CYP and UGT Supersomes. The CYPand/or UGT-mediated metabolism kinetics were examined simultaneously or individually. Relative activity factor and total normalized rate approaches were used to assess the relative contributions of each major human CYPs towards the FA metabolism. Incubations of FA with human liver microsomes(HLM) displayed NADPH-and UDPGA-dependent metabolism with multiple CYP and UGT isoforms involved. CYPs and UGTs contributed equally to the metabolism of FA in HLM. Although CYP1 A2 and CYP3 A4 appeared to be the major contributors in the CYP-mediated clearance, their contributions to the overall clearance are still minor(< 25%). As a constitute of many food and herbs, FA poses low drug-drug interaction risk when co-administrated with other herbs or conventional medicines because multiple phase I and phase II enzymes are involved in its metabolism. One, the best documented activities of FA is its antioxidant property. Moreover, FA exerts antiallergic, anti-inflammatory, and hepatoprotective effects. However, the metabolic pathways of FA in human remain To identify whether human CYP or UGT enzymes are involved in the metabolism of FA, reaction phenotyping of FA was conducted using major CYP-selective chemical inhibitors together with individual CYP and UGT Supersomes. The CYP and / or UGT-mediated metabolism kinetics were examined simultaneously or individually. Relative activity factor and total normalized rate of cells were used to assess the relative contributions of each major human CYPs towards the FA metabolism. Incubations of FA with human liver microsomes (HLM) displayed NADPH-and UDPGA-dependent metabolism with multiple CYP and UGT isoforms involved. CYPs and UGTs contributed equally to the metabolism of FA in HLM. to be the major contributors in the CYP-mediated clearance, their contributions to the overall clearance are still minor (<25%). As a constitute of many food and herbs, FA poses low drug-drug interaction risk when co-administered with other herbs or conventional medicines because multiple phase I and phase II enzymes are involved in its metabolism.