It was showed from the anti-virus experiment in vitro that 8mg crude drug/ml of Guizhi decoction could inhibit cytopathy induced by 10 strains of viruses associated with respiratory infection at the different extents.From the in vitro experiment with rats′serum after the oral administration of Guizhi decoction

it was found that the serum(1∶4) could inhibit the proliferation of four strains of viruses including herpes simplex virus I type in Hep-2 cells.The serum had no obviously decreased effects after stored at -20℃.Normal rats′serum also could weakly delay the effects on cytopathy induced by the viruses.