The aerial parts of three species from Labiatae (Thymus carmanicus Jalas, Salvia hypoleuca Benth. and Teucrium Stocksianum Boiss.) from Iran were obtained by hydrodistillation in a clevenger-type apparatus for 3h (2%, 0.3% and 0.5%, respectively). The species were collected from Karkas-Kuh (Natanz area, Province Isfahan), Ab-ali (North of Tehran) and Siahoo, North of Bandar-Abbas, Province Hormozegan), respectively. This oil has been examined by GC and GC/MS. The components of the oil were identified by comparison of their fragmentation patterns of mass spectra and retention indices with those published in the literature and presented in the MS computer library. In the oil of T. carmanicus, monoterpenes predominated over sesquiterpenes. Thymol and carvacrol were the major components of the oil, 20.8 and 52.8%, respectively. Other components were η-terpinene (5.4%), p-cymene (4.1%) and borneol (1.5%). In the oil of T. Stocksianum α-pinene (24.5%) and α-copaene (3.4%) were major compounds; and in the oil of S. hypoleuca, bicyclogermacrene (15.3%), β-caryophyllene (14.6%), viridiflorol (13.3%), spathulenol (12.5%) δ-elemene (7.7%), β-pinene (7.2%) and α-pinene (5.9%) were major compounds.
