We examined the anti-influenza virus activity of tricin, 4',5,7-trihydroxy-3',5'-dimethoxyflavone, against five viruses: A/Solomon islands/3/2006 (H1N1), A/Hiroshima/52/2005 (H3N2), A/California/07/2009 (H1N1pdm), A/Narita/1/2009 (H1N1pdm) and B/Malaysia/2506/2004 strains in vitro and against A/PR/8/34 virus in vivo.