Echinacea purpurea aerial extract alters course of influenza infection in mice.

Influenza infection is a major clinical problem and Echinacea purpurea, a widely consumed botanical product, is purported to alter the course of respiratory infections including influenza. Mice infected with WSN influenza A and treated with E. purpurea polysaccharide extract had less weight loss than untreated mice but similar pulmonary viral titers. Echinacea-treated mice had lower systemic and pulmonary KC and IL-10 levels and lower systemic IFN-gamma levels following influenza infection. These suggest that E. purpurea alters the clinical course of influenza infection in mice through modulation of cytokines and not direct antiviral activity.