In the present work, 70 extracts from 23 plants have been determined to induce cytotoxic and antiviral activities of macrophages using both MTT assay and neutral red dye uptake assay. We show that 13 extracts have induced cytotoxic activities and 5 extracts induced antiviral activity in mouse peritoneal macrophages. Among 13 extracts, macrophages treated with extracts from Salvia plebeia have demonstrated significant cytotoxicity but not antiviral activity. The present findings indicate that extracts from plants can stimulate macrophages to become resistant to virus and to kill tumor cells.