Handayeolso-Tang(HDT) has been used as traditional medicine for the treatment of Taeumin TaeYang-Hanguel. The present study was conducted to investigate the anti-allergic activity of Handayeolso-Tang(HDT). We investigated the anti-allergic effects of HDT in RBL-2H3 basophilic leukemia cells by compound48/80, a mast cell degranulator and compound 48/80 induced anaphylactic shock in mice. HDT significantly inhibited ${eta}-hexosaminidase$ and histamine release from compound 48/80 stimulated RBL-2H3 cells. In addition, HDT effectively inhibited anaphylactic shock in mice by 45% at a dose 120 mg/mouse versus PBS treated control after the I.p injection(8 mg/kg) of compound 48/80. The in vitro anti-inflammatory activities of HDT in LPS-stimulated RAW 264.7 cells were investigated. HDT inhibited NO production in LPS-stimulated RAW 264.7 cells and effectively dowregulated the expression of iNOS mRNA and iNOS protein expression in LPS -stimulated RAW 264.7 cells. These result provide evidences that HDT may be beneficial in the treatment of allergic inflammtory disease.