Abstract: To investigate the inhibitory effect of Pluronic on P-glycoprotein (P-gp) drug efflux pump, Caco-2 cells and animal models were established to study the influence of Pluronic on celiprolol transport across Caco-2 cell monolayer and intestinal mucous membrane with verapamil set as a positive control. Drug concentration was measured by HPLC and the apparent permeability coefficient (P_app), absorption rate constant (k_a) and the effective permeability coefficient (P_eff) were calculated. P_app of basolateral to apical side and apical to basolateral side was (2.10 ± 0.13)×10^-6 and (0.333 ± 0.018)×10^-6 cm·s^-1, respectively. Transports of celiprolol across Caco-2 cell monolayer were influenced by both verapamil and Pluronic. The absorption constants (k_a) of celiprolol at duodenum, jejunum, ileum, and colon were (0.09±0.03), (0.14±0.04), (0.11±0.03) and (0.05±0.02) h^-1, k_a of celiprolol in verapamil group were (0.14±0.03), (0.24±0.02), (0.25±0.03) and (0.23±0.02) h^-1, and k_a of celiprolol in Pluronic group were(0.13±0.02), (0.22±0.02), (0.22±0.03) and (0.20±0.03) h^-1, respectively. Pluronic showed significant effect on inhibiting P-gp of Caco-2 cell and intestinal mucosa in rats.