The antiviral activities of houttuynia cordata(H.cordata) aqueous extract against dengue virus serotype 2, strain 1668, were evaluated in this study.The results showed that pre-and post-incubation of H.cordata extract with HepG2 cells significantly neduced intracellular DEN-2 RNA production corrlating with the decrease in dengue protein expression.In the direct blocking mode,the extract bound with DEN-2 and strongly inhibited the intracellular virak RNA replication with an effective dose of Concentrations as low as extract also exhibited protective effect on virion release from infected LLC-MK2 CELLS.High-performance liquid chromatography analysis of extract indicated that hyperoside was the predominant bioactive compound, and was likely to play a role in this inhibition.The extract was also shown to have no genotoxic effect on human blood cells.