. "The tea polyphenol compounds as the principal effective ingredients in the inventive medicament against infection with influenza virus include the tea catechin compounds represented by the general formula (I) given below and the theaflavin compounds represented by the general formula (II) given below: ##STR1## in which R1 is a hydrogen atom or a hydroxy group and R2 is a hydrogen atom or a 3,4,5-t" . . . . .