Abstract: OBJECTIVE To study the transmembrane absorption characteristics of paeoniflorin from Kunfukang tablets in Caco-2 cell model, and to explore the absorption and transport of paeoniflorin in human small intestine.METHODS The effects of different drug concentrations, pH, temperature and inhibitors on the bidirectional permeability of albiflorin from the apical(AP) to the basolateral(BL) side of Transwell plate cells and in the reverse direction was studied.RESULTS When administered at three concentrations(5, 20 and 100 μmol·L^-1), the apparent permeability coefficient(P_app) value in the AP-to-BL direction ranged in (3.27-5.37)×10^-7 cm·s^-1. In the reverse direction, BL-to-AP, the P_app value was ranged in (6.64-9.63)×10^-7 cm·s^-1. The data indicated that albiflorin transport was pH-and temperature-dependent. The permeability of albiflorin was affected by treatment with various inhibitors, such as Na⁺/K⁺ pump inhibitors sodium vanadate, multidrug resistance protein inhibitors MK571 and indomethacin, as well as the breast cancer resistance protein inhibitor apigenin. After the addition of Kunfukang pills, the P_app values in the AP-to-BL direction increased significantly.CONCLUSION Albiflorin is shown to be a poorly absorbed compound in the Caco-2 cell monolayer model, and its absorption mechanism may involve a variety of protein mediated active transport.