Objective:To investigate the inhibitory effect of glycyrrhizin on HSV-1 in vitro

and to search a new drug against herpes simplex encephalitis.Methods:The Vero cells were cultured and divided into three groups:the group treated with glycyrrhizin after absorption of HSV-1 into the Vero cells

the group of pretreated cells and the group of pretreated HSV-1 with both glycyrrhizin before absorption of HSV-1 into the Vero cells.The plaque formation units were observed to evaluate the inhibitory effect of glycyrrhizin on HSV-1 and the stage when the virus replicating was inhibited.Results:Glycyrrhizin treatment after the absorption of virus into the cells obviously reduced the plaque formation units due to the virus infection and IC 50 was 0.56mM.Pretreated cells and pretreated HSV-1 with glycyrrhizin before absorption of HSV-1 into the cells did not reduce the plaque formation units.Conclusion:Glycyrrhizin can markedly inhibit the replication of HSV-1 in Vero cells.Glycyrrhizin can not inhibit the virus absorption and inactivate the virus.