The effect of an aqueous horse-radish extract, applied as such or in association with caffeine, on experimental influenza in mice.

An aqueous horse-radish extract was repeatedly administered to mice by intranasal (i.n.) route prior to i.n. inoculation of influenza virus A/PR8/34 (H1N1). The antiviral effect of the extract--also demonstrated in vitro--was reflected by a significant decrease in the hemagglutination titers recorded in mouse lung homogenates and by a slight increase in the mean survival time of treated mice versus untreated controls. Association of horse-radish extract with caffeine led to a synergic effect only as regards the mortality rate.