Abstract: AIM: To study the antiviral effects of the complex of Hypericum perforatum L and lysine hydrochloride against herpes simplex virus type 1 and varicella-zoster virus (VZV), and to evaluate the LD50 of the complex in mice.METHODS: The cytotoxities to Vero cells and 2BS cells and the antiviral activities were evaluated by cytopathic effect (CPE) inhibition assay.ICR mice were administrated(ig) the complex (2 ∶1) to determine LD50.RESULTS: The complex significantly inhibited the CPE of HSV-1 and VZV.MIC ranged from 9.7 to 19.5 mg·L^-1, IC50 ranged from 6.8 to 9.7 mg·L^-1.LD50 of the complex with ratio 2 ∶1 was 11.7 g·kg^-1 with 95 % confidence interval of 6.5-17.2 g·kg^-1 in ICR mice.CONCLUSION: The complex of Hypericum perforatum L and lysine hydrochloride has good effects on inhibiting HSV-I and VZV in vitro.The complex (2 ∶1) is safe in mice.

Key words: Hypericum perforatum L, lysine hydrochloride, complex, HSV-I, VZV, LD50