antiviral activity of aspalathus linearis against human influenza virus influenza a viruses are responsible for annual epidemics and occasional pandemics which cause significant morbidity and mortality the limited protection offered by influenza vaccination and the emergence of drugresistant influenza strains highlight the urgent need for the development of novel antiinfluenza drugs however the search for antiviral substances from the library of low molecular weight chemical compounds is limited thus because of their natural diversity and accessibility plants or plantderived materials are rapidly becoming valuable sources for the discovery and development of new antiviral drugs in this study crude extracts of aspalathus linearis a plant reported to have antihiv activity were evaluated in vitro for their activity against the influenza a virus of the extracts tested an alkaline extract of aspalathus linearis demonstrated the strongest inhibition against influenza a virus and could also inhibit differenttypes of influenza viruses including oseltamivirresistant influenza viruses a and b our time course of addition studies indicated that the alkaline extract of aspalathus linearis exerts its antiviral effect predominantly during the late stages of the influenza virus replication process