Chaerophyllum libanolicum Boiss. et Kotschy from Apiaceae, is collected and used as a food plant in Turkey. The essential oil obtained by hydrodistillation from the crushed fruits of C lihanoticuin collected from Osmaniye, Southern Turkey, was simultaneously analysed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). As a result, a total of seventy three components were characterized, representing 98.3% of the total oil with monoterpenes as the major group. The principal constituents were identified as beta-phellandrene (17.6%), limonene (15.9%), beta-pinene (8.8%), and sabinene (8.5%), respectively. The essential oil was evaluated for its antimicrobial activity using a microdilution assay resulting in the inhibition of a number of common human pathogenic bacteria including methicillinresistant Staphylococcus aureus (MRSA) and the yeast Candida albicans. The minimum inhibitory concentrations (MIQ varied between 0.25 and 0.5 mg/mI which is within a moderate antimicrobial activity range. Furthermore, the antioxidant capacity of the essential oil was examined using an in vitro radical scavenging activity test. The C libanoticum essential oil scavenged 1,1-diphenyl-2-picrylhydrazyl radical (DPPH,), resulting in IC50 > 30 mg/ml. In addition, the effect on inhibition of lipid peroxidation of the essential oil was assayed using P-carotene bleaching and haemoglobin induced linoleic acid peroxidation methods resulting in 16% antioxidative activity. (c) 2007 Elsevier Ltd. All rights reserved.