Genus Curcuma (Zingiberaceae) has long been used as a folk medicine. The essential oils of dried rhizomes of C. aromatica Salisb., C. longa L. and C. sichuanensis X. X. were isolated using simultaneous steam-distillation and solvent-extraction apparatus. In total, twenty-three compounds were
identified as essential oils, including ten terpenes, six alcohols, two ketones and five other compounds.The major compounds were curcumol (35.77%) and 1,8-cineole (12.22%) for C. aromatica,ar-turmerone (49.04%), humulene oxide (16.59%) and β-selinene (10.18%) for C. longa, and
ar-turmerone (43.52%), β-selinene (13.36%) and δ-cadinene (13.22%) for C. sichuanensis. EC50 values of antioxidant activities of the essential oils were 3.19-19.63 mg/mL and the effectiveness was, in descending order: C. longa > C. sichuanensis > C. aromatica. EC50 values of scavenging abilities on 1,1-diphenyl-2-picrylhydrazyl radicals were 8.29-15.54 mg/mL and the effectiveness was in a descending order: C. aromatica > C. longa > C. sichuanensis.