Petasites extract and composition and method for treating viral infections

A method for the treatment of a viral infection in a mammal in need thereof, comprising the step of administering to the mammal in need thereof, an effective amount of a Petasites extract or composition comprising an effective amount of a Petasites extract, wherein the effective amount of the Petasites extract or the composition comprising the effective amount of the Petasites extract is effective in treating the viral infection, and wherein the Petasites extract is made by extraction of the Petasites with liquid carbon dioxide.