Abstract: OBJECTIVE To investigate the transepithelial transport of centaureidin across Caco-2 cell monolayers. METHODS The permeated amounts of centaureidin across Caco-2 cell momnolayers were measured by HPLC to calculate the permeation rate and the apparent permeability coefficient (P_app), based on the effect of absorption time, drug concentration, pH in apical side, and inhibitors, the Papp was determined. RESULTS Transport of centaureidin was concentration-dependent and time-dependent and nonsatuable. The acidic pH in apical side conduced to transepithelial transport of centaureidin. Though 2,4-dinitrophenol had no effect on transport of centaureidin, verapamil improved it. And the apical-to-basolateral P_app was less than the basolateral-to-apical P_app. CONCLUSION Transport of centaureidin across Caco-2 cell monolayers is via passive diffusion with efflux by P-glycoprotein.