ABSTRACT The chemical compositions of the essential oils obtained by hydrodistillation from aerial parts of five subspecies of Scutellaria orientalis L. (subsp. carica, subsp. haussknechtii, subsp. macrostegia, subsp. orientalis and subsp. santolinoides) were analyzed by gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS), simultaneously. According to essential oil analysis in five subspecies of S. orientalis, germacrene D (57.2%), bicyclogermacrene (7.4%) and β-caryophyllene (5.2%) in subsp. carica; germacrene D (23.5%), β-caryophyllene (14.2%), bicyclogermacrene (9.0%) and caryophyllene oxide (8.1%) in subsp. haussknechtii; germacrene D (47.8%), β-caryophyllene (16.3%) and bicyclogermacrene (12.0%) in subsp. macrostegia; caryophyllene oxide (23.5%), germacrene D (20.1%) and β-caryophyllene (14.5%) in subsp. orientalis; germacrene D (42.1%), β-caryophyllene (13.7%) and bicyclogermacrene (11.3%) in subsp. santolinoides were determined as major components. To the best of our knowledge, this is the ï¬rst report on the chemical composition of the essential oil of four subspecies of S. orientalis.