Abstract: The chemical constituents of the essential oil of Myristica Fragrans Flo-att were analysed by GC/MS. 19 compounds have been identified, i. e. a-pinene, α-thujene, β-thujene, β-pinene, myrcene, α-phellandree, β-terpine-ne, terpinolene, butylbenzene, limonene, γ-terpinene, α-terpinene, β-ter-pineol, terpineol-4, α-terpineol, fafrole, methyleugenol, α-copaene and my-risticine. The cleavage mechanism of three oxy-compounds: fafrole, methy-leugenol and myristicine have also been discussed.