Abstract:Volatile oil was extraeted from the rhizome of Citotium barometz for the first time. Its content wasdetermined to be 83. 3μg/g, decreasing significantly after the drug was processed. Twelve constituents from thevolatile oil were identified by method of GC-MS. The main constituents were organic acids. The contents of palmiticacid and linoleic acid were the highest. After Cibotium barometz was processed ,some constituents were found decreas-ing and some increasing.