the essential oil content in the roots of chrysopogon aucheri growing wild in south of iran was found to be 0.1% based on the fresh weight. the oil was analyzed by gas chromatography (gc) and gas chromatography-mass spectrometry (gc/ms). twenty constituents were identified, which approximately constituted 97.3% of the root oil. monoterpenes consist more than 88% of the oil of which the major components were characterized as -pinene (23.1%), (e)--ocimene (20.9%), (z)--ocimene (12.0%) and -phellandrene (10.8%).