The antiviral spectrum of Listerine antiseptic.

The mechanism of activity and the antiviral spectrum of Listerine antiseptic have not been examined thoroughly. We therefore tested its effect on laboratory strains of herpes simplex type 1 and type 2 (enveloped DNA viruses), influenza A virus (enveloped RNA virus), rotavirus (nonenveloped RNA virus), and adenovirus type 5 (nonenveloped DNA virus). Each virus was mixed with an equal volume of Listerine for 30 seconds to 5 minutes, and the residual infectivity of the virus was assessed. An antiviral effect was defined as greater than 95% reduction of infectivity. Exposure to Listerine for 30 seconds had an antiviral effect against herpes simplex type-1 and type-2 (96.3% and 100% reduction in infectious virus, respectively) and influenza A (100% reduction). In contrast, rotavirus-induced plaque formation was reduced by 12.2% after 30 seconds of exposure to Listerine, whereas 5 minutes of exposure to Listerine resulted in a 21.5% increase in plaque formation. Exposure of adenovirus to Listerine had a minimal effect on the cytopathocity of the virus, with a 33.4% reduction in virus levels after 5 minutes. The antiviral activity of Listerine is thus not related to the viral genome but is probably directed to the viral envelope.