abstract the essential oils from the leaves and stems of ferula szowitsiana dc. (umbelliferae) were separately obtained by hydrodistillation and then analyzed by gc and gc/ms methods. the oil yields were 0.4% and 0.05%, respectively. one-hundred and sixty-two compounds representing 99.5% and 99 compounds representing 94.4% were identified in the leaf oil and stem oil, respectively, with -eudesmol (32.0% and 29.5%, resp.), -eudesmol (18.2% and 16.6%, resp.) and -pinene (8.6% and 6.4%, resp.) as the major constituents. antimicrobial activity of the leaf oil was tested via in-vitro microdilution broth technique. escherichia coli, pseudomonas aeruginosa, proteus vulgaris, salmonella typhimurium, staphylococcus epidermidis, methicillin-resistant staphylococcus aureus, and candida albicans were used as the test microorganisms.