The present work examines the in vitro antioxidant properties of the essential oil and various extracts prepared from the herbal parts of Ferula orientalis A. (Apiaceae). The highest 2,2-diphenyl-l-picrylhydrazyi (DPPH) radical-scavenging activity was found in the polar extract, e.g. methanol-water (1:1), obtained from non-deodorised materials with IC50 values at 99.1 mu g/ml. In the beta-carotene/linoleic acid assay, the deodorised acetone extract exhibited stronger activity than the polar one. The relative antioxidant activities (RAA%) of the extracts ranged from 10.1% to 76.1%, respectively. Extraction with methanol-water (1:1) mixture was concluded to be the most appropriate method in terms of higher extract yield, as well as effectiveness, observed in both assays. Although the essential oil showed antioxidative potential, it was not as strong as that of positive control (BHT). GC/MS analysis of the essential oil resulted in the identification of 39 compounds, beta-phellandrene (23.6%), (E)-beta-ocimene (13.8%), alpha-pinene (12.5%), alpha-phellandrene (11.5%) and dehydro-sesquicineole (10.1%) being the major components. (c) 2005 Elsevier Ltd. All rights reserved.