The effect of the aqueous extract of Rubus coreanus Miq. (Rosaceae) fruits (AERC) on anaphylactic reaction was investigated. AERC completely inhibited compound 48/80-induced systemic anaphylactic shock at dose of 0.1 to 1.0 g/kg. When AERC was pretreated at concentrations ranging from 0.01 to 1.0 g/kg, the plasma histamine levels induced by compound 48/80 were reduced in a dose-dependent manner. AERC also inhibited the histamine release from rat peritoneal mast cells (RPMC) by compound 48/80. The level of cAMP in RPMC, when AERC (1.0 mg/ml) was added, transiently and significantly increased about 6-fold compared with that of basal cells. These results indicate that AERC may be beneficial in the treatment of non-specific anaphylactic reactions.