The present invention concerns polysaccharide extracts of epimedium and, in particular, concerns total polysaccharide extracts of Chinese-medicine medicinal grade leaves of epimedium, acidic polysaccharide fractions and non-polysaccharide fractions thereof and their use in the preparation of vaccine adjuvants, vaccines, vaccine compounds or antibodies. The present invention also concerns medicinal compounds, vaccine adjuvants, vaccines or vaccine compounds comprising total polysaccharide extracts of epimedium and their fractions.