The volatile constituents of the roots of Arctium lappa LINN (Compositae family) was investigated by GC, GC-MS, IR and NMR. Nine hydrocarbons, 19 aldehydes, 7 2-alkyl-3 - methoxypyrazines, 32 acids and 2 sesquiterpenoids were identified. Aplotaxene, dehydrocostus lactone, dehydrodihydrocostus lactone and costic acid were isolated and identified as major components.