The effect of aqueous extract of Salvia plebeia R. Br. (Labiatae) (AESP) on immunoglobulin (lgE) antibody mediated allergic reactions in rats was investigated. AESP inhibited passive cutaneous anaphylaxis (PCA) when intravenously, intraperitoneally, and orally administered. AESP dose-dependently inhibited histamine release from rat peritoneal mast cells activated by anti-DNP IgE antibody. Moreover, AESP had an inhibitory effect on anti-DNP IgE antibody induced $TNF-{alpha}$ production from RPMC. These results suggest that AESP inhibit the IgE-mediated allergic reaction in rats.