Objective:To evaluate the combination of saponins of Glycyrrhiza uralensis Fisch(GS) and Platycodon grandiflorum A.DC(PS) for duration of expectorant and anti-inflammatory effects.Methods:The duration of effects was observed directly in phenol drain model

xylene-induced mouse ear edema model and PLA2-induced mouse paw edema model

and the combinative effects of two agents was evaluated quantitatively by Jin's Q formula.Results:Co-administration of GS and PS in 8∶1 can extend the duration of expectorant and anti-inflammatory effects

when compared to any agent alone.By the method of Jin's Q formula

additivity

synergism or antagonism was obtained in different models.Conclusions:GS and PS combined have characteristic of synergism in duration of expectorant and anti-inflammatory effects.The combinative ratio and total dose are two factors that can affect the combinative effects.