The methanolic extract of the roots of Asiasarum sieboldi has been evaluated for anti-allergic effects on various experimental models in vitro and in vivo. Bioassay-guided fractionation of the methanolic extract resulted in isolation of suppressive compounds in the PCA test: methyleugenol (1), elemicin (2), gamma-asarone (3), (-)-asarinin (4), and (-)-sesamin (5). Furthermore, elemicin (2) and (2E,4E,8Z,10E)-N-isobutyl-2,4,8,10-dodecatetraenami de (6) were found to exhibit an inhibitory action on 5-lipoxygenase (5-LOX) from RBL-1 cells. 3',4'-Dimethoxycinnamaldehyde (7) and xanthoxylol (8) potently reduced the contractile response of guinea pig ileal strips to LTD4.