Whereas for the extract of V. thapsus, antiherpes activity has been reported (29); our study revealed only the strong anti-influenza viral activity. However, no antiviral compounds have previously been isolated. The plant is known to contain phenylethanoid and lignan glycosides (30) . On the other hand, the phytochemicals responsible for anti-influenza viral activity could be different from anti-herpes activity and also the amount of active constituents present in the plants depends on the geographical distribution, season of collection and climatic and ecological condition at the collection site. Looking at the chemical structures of the already identified compounds, most of these substances should be extracted by methanol. The foregoing extraction by more lipophilic solvents (n-hexane and dichlormethane) alleviates the methanolic extraction and the planned fractionation.