The discovery of drugs on the treatment of mast cell-mediated allergic disease is a very important subject in human heath. The Socheongyoug-tang(SCYT) has been used for centruries as a traditional medicine in Korea and is known to have an anti-inflammatory effect. However, its specific mechanism of action is still unknown. In this report, we investigated the effect of hot water extract from SCYT on RBL-2H3 mast cell-mediated allergic reaction and studied its possible mechanism of action. SCYT inhibited compound 48/80-induced systemic anaphylaxis and serum histamine release in mice. SCYT decreased the passive cutaneous anaphylaxis reaction activated by Anti-lgE antibody-HSA. SCYT dose-dependently reduced histamine release from mice peritoneal mast cells activated by Anti-lgE antibody-HSA. SCYT increased cAMP and decreased compound 48/80-induced intracellular $Ca^{2+}$ levels. Our findings provide evidence that SCYT inhibits mast-derived allergic reactions, and also demonstrate the involvement of cAMP and intracellular $Ca^{2+}$ in these effects.