Satureja species are commercially and medicinally important due to their high variability of essential oil components. In this study the essential oil compositions of eleven individual plants of Satureja macrosiphonia Bornm (Labiatae) from Ilam province (Iran) were characterized. The oils were isolated from flowering aerial parts of the plants by hydro-distillation method and then subjected to GC and GC-MS analyses to determine the constituents. Forty-two compounds were identified in the essential oils. The oil of S. macrosiphonia was rich in oxygenated monoterpens (ranging from 31.1 to 77.1 %) and monoterpene hydrocarbons (from 14.5 to 60.7 %). Limonene (0.2-20.1 %), β-phellandrene (0.2-22.9 %), γ-terpinene (1.0- 21.1 %), trans-sabinene hydrate (1.2-15.0 %), cis-linalool oxide (0.4-30.5 %), linalool (0.1-15.5 %), cissabinene hydrate (0.2-24.5% ), p-menth-2-en-1-ol (0.9-28.0 %), borneol (0.2-8.2 %), 4-terpineol (0.2-24.0 %) and crvacrol (0.2-5.7 %) were the major essential oil constituents. Variation of essential oil constituents found in this study represents the S. macrosiphonia as a unique chemotype in comparison to the other Satureja species.
