The anti-inflammatory activity of nine isoflavonoids 5,7-dihydroxy-3-(3'-hydroxy-4',5'dimethoxy)-8-methoxy-4H-1-benzopyran-4-one 1, 5,7-dihydroxy-3-(3'-hydroxyl-4', 5'-dimethoxy)-6-methoxy-4H-1-benzopyran-4-one 2, 5, 7-dihydroxy-3-(4'-hydroxy)-6-methoxy-4H-1-benzopyrane-4-one 3, 5-hydroxy-3-(4'-hydroxy)-6,7-methylenedioxy-4H-1-benzopyran-4-one 4, 5-hydroxy-3-(4'-methoxy)-6,7-methylenedioxy-4H-1-benzopyran-4-one 5, 5-methoxy-3-(4'-hydroxy)-6,7-methyenedioxy-4H-1-benzopyran-4-one 6, 5,7-dihydroxy-3-(3'-hydroxy-4'-methoxy)-6-methoxy-4H-1-benzopyran-4-one 7, 5,7-dihydroxy-3-(3'-methoxy-4'-hydroxy)-6-methoxy-4H-1-benzopyran-4-one 8, and isopeonol 9 determined by a spectrophotometric assay using the activated human neutrophils. These isoflavonoids were isolated from an important folkloric medicinal plant Irsa (Iris germanica L.), a member of the family Iridaceae. Structures of these compounds were identified by spectral comparison with the reported data and active members of this group adds into the growing number of non-steroidal anti-inflammatory agents.