The oil (I) of b.p2.5-3 96-99° was fractionated from the ethanolic extract of the rhizome of Ligusticum scoticum L. and this substance was determined as myristicin from its physical and chemical properties. Bromination of (I) in the cold gives dibromomyristicin dibromide (II) while treatment of (I) in alkali resulted in isomerization, and its bromo compound (IV) was also obtained. Permanganate oxidation of (I) gave (V), which was proved by separation of gallic acid. The fact that hydrogenation of (I) and (III) afforded the same derivative also indicates the position of double bond in the side chain. These results prove that the substance is myristicin.