Objective:To elucidate inhibitory effect of placental active factor (PAF) on herps simplex virus (HSV) in cell cultures.Methods:The antiviral effect of drug was examined by an indirect immunofluorescence assay.Results:The fact that viruses absorb cells can not be prevented by PAF.This showed that direct killing and inhibitory effect of PAF for HSV is involved.The inhibitory concentraction is 100 μg/ml.The result is best at 8th hour than any other times.Conclusions:This PAF is nontoxic,harmless and produces ...