The Salvia plebeia R. which is the biennial plant belonging to the labiatae department, grows widely in Korea. This study was performed to evaluate the antioxidant activities and anti-allergic effects of Salvia plebeia R. leaves (SPLE) or roots (SPRE). Using ethanol extracts, both leaves and roots induced significant radical scavenging activity against DPPH and ABTS radicals in a dose dependent manner (p<0.05). Superoxide dismutase (SOD)-like activity of SPLE was significantly higher than that of SPRE at all concentrations. Treatment of the RBL-2H3 cells with SPLE and SPRE in vitro decreased ${eta}$-Hexosaminidase release and significantly inhibited IgE-antigen complex-mediated IL-4 and TNF-${alpha}$ mRNA expression in RBL-2H3 cells. These findings suggest that Salvia plebeia R. can protect or reduce allergic asthma through high antioxidant and anti-allergic reactions.