Aim:To investigate whether baicalin and berberine affects the transport ofnimodipine (NMD) across the blood-brain barrier (BBB).Methods:Primary-cultured,rat brain microvascular endothelial cells (rBMEC) were used as an invitro model of the BBB.When cells became confluent,the steady-state uptake ofNMD by rBMEC with or without baicalin and berberine was measured.The ef-fects of baicalin and berberine on the efflux of NMD from rBMEC were also studied.Results:Baicalin (2-5 μg/mL) increased the uptake of NMD,and baicalin (10-20μg/mL) decreased the uptake.The steady-state uptake of NMD was higher thanthat of control group in the presence of 0.01-1 μg/mL berberine,but was lower inthe presence of 2-10 μg/mL berberine.Conclusion:The bidirectional effect ofbaicalin and berberine on the uptake of NMD by rBMEC was found.Higherconcentration showed an inhibitory effect,and lower concentration demonstratedan increasing effect. Aim: To investigate whether baicalin and berberine affects the transport of nimodipine (NMD) across the blood-brain barrier (BBB). Methods: Primary-cultured, rat brain microvascular endothelial cells (rBMEC) were used as an invitro model of the BBB.When The cells became confluent, the steady-state uptake of NMD by rBMEC with or without baicalin and berberine was measured. The ef-fects of baicalin and berberine on the efflux of NMD from rBMEC were also studied. Results: Baicalin (2-5 μg / mL ) increased the uptake of NMD, and baicalin (10-20 μg / mL) decreased the uptake.The steady-state uptake of NMD was higher thanthat of control group in the presence of 0.01-1 μg / mL berberine, but was lower inthe presence of 2-10 μg / mL berberine.Conclusion: The bidirectional effect ofbaicalin and berberine on the uptake of NMD by rBMEC was found .Higherconcentration showed an inhibitory effect, and lower concentration demonstratedan increasing effect.