Objective:To investigate the effect of Coptis-scute herb and combined（2∶1

1∶1） use on the P-glycoprotein function in rat jejunum.Method: The rats were randomly divided into five groups.Rhodamine 123（R123） and fluorescein sodium（FS）

a P-gp substrate and a non-P-gp substrate model drug were taken as investigating indicator.After oral administration of four different decoctions of Coptis-scute herb and its combination（2∶1

1∶1） for successive 7 days

the cumulative permeability percentage and the apparent permeability coefficient（Papp） of R123 or FS were evaluated by applying a rat everted gut sac as well as a non everted gut sac method.Result: The absorptive directed permeability（mucosa to serosa

M-S） of R123 can be increased after oral administration of Coptis decoction

and on the other hand

the secretory directed transport（serosa to mucosa

S-M） be decreased

but there is no significant effect.The other three groups can increase M-S of R123 as well as reduce S-M

but there is no significant difference on the S-M after oral administration of Scute decoction.In parietal cells transport of FS

no significant effect can be found in Coptis-scute herb and its combination 2∶1 group on two direction transport but decreased effect can be found in combination1∶1 group.Comparing with the efflux ratios（ER） of physiological saline

there are no significant differences on the four groups.Conclusion: Coptis could increase P-gp activity

and Scute may have opposite effect.The rest of the two groups have stronger inhibition than Scute.1∶1 group was the strongest one

followed by 2∶1

the weakest was the Scute group.