Research carried out at the Pharmaceutical School of Campinas University in 2008 investigated the effectiveness of propolis on the influenza virus, causing common flu under in vitro conditions in mice. The experiment was conducted with propolis prepared in alcohol. The results of the study showed that propolis was effective in controlling the reproduction of the virus and decreased flu symptoms. The scientists suggested that alcohol extract of propolis is a beneficial dietary supplement for humans against the influenza virus.

Reference:Shimizu, T., Hino, A., Tsutsumi, A., Park, Y.K., Watanebe, W. & Kurokawa, M. 2008. Anti-influenza virus activity of propolis in vitro and its efficacy against influenza infection in mice. Antiviral Chemistry & Chemotherapy, 19: 7-13.