Flavonoids have been previously shown to possess anti-viral activities In vitro. Oroxylin A-7-O-β-D-glucoside (OAG), a flavonoids produced by microbial conversion, and its substrate baicalin, were assayed for antiviral function against hepatitis B virus (HBV), herpes simplex virus type 2 (HSV-2) and influenza A virus (H3N2).