We have recently shown that the essential oil extracted from the Lebanese sage plant (Salvia libanotica) has potent chemopreventive effects against mouse skin carcinogenesis. This oil was also found to be a potent anti-inflammatory agent in the skin of treated mice. In order to investigate the mechanisms by which sage essential oil inhibits skin tumor promotion, one should first identify the bioactive components found in this plant. Using GC analyses, we identified 12 different individual components in sage essential oil. The present investigation is undertaken to determine the nature of the agent responsible for the observed anti-tumor promoting effects of the oil extract of sage. Anticancer activity will be determined by screening for antiproliferative activity against cancer cell lines grown in vitro when the components are applied alone or in combination. We will further define the mechanism of action of the drugs. This study will help verify and enhance the understanding of medicinal and other beneficial bioactivities suspected from ethnobotanical and historical uses of Lebanese sage.