The effects of a mixture of tea-seed saponins obtained from the seeds of Camellia sinensis var. sinesis on human influenza viruses types A and B were investigated. At the concentrations of 60, 80, and 100 micrograms/ml, respectively, the mixture inactivated viruses A/Memphis/1/71 (H3N2), B/Lee/40, and A/PR/8/34 (H1N1) almost completely. The mixture also inactivated type A virus A/PR/8/34 after inoculation at concentrations of 1-30 micrograms/ml dose-dependently.