The present invention provides an antiviral mediacament for treating Japanese Encephalitis Virus (JEV) infection comprises a natural falvonoid compound namely baicalein. In the present invention, antiviral activity of baicalein was evaluated against JEC replication in African green monkey kidney cell line (Vero). anti-JEV activities of baicalein were examined at different stages of JEV replication cycle. The effects of baicalein on virus replication were determined form Foci Forming Unit Reduction Assay (FFURA) and quantitative RT-PCR