Variations in the essential oil composition of Foeniculum vulgare Mill. commercial fruits obtained from retail pharmacies in Estonia, Norway, Austria and Moldova and from a spice shop in Turkey were determined using capillary GC techniques. The essential oil content of all the samples was 5-51 mL kg(-1) and between 22 and 51 mL kg(-1) in fennel fruits bought from pharmacies. A total of 34 compounds were identified. The major component was trans-anethole (34.8-82.0%); the other principal compounds in oils were fenchone (1.6-22.8%), estragole (2.4-17.0%), limonene (0.8-16.5%), and cis-anethole (0.1-8.6%). The yield of essential oil (5.0 mL kg(-1)) and content of trans-anethole was very low (34.8%) in the Turkish spice sample. Maximum yield of essential oil was found in fennel from Norway and Austria (50.7 and 50.5 mL kg(-1), respectively); these samples were rich in fenchone (21.2% and 22.8%), but contained less trans-anethole (64.6-63.7) than samples from Estonia and Moldova (82.0% and 80.9%). The typical samples of sweet fennel (bought from Estonia and Moldova) and bitter fennel (from Norway and Austria) were found to conform completely or partially to EP standards, although fennel type was always not marked on the packages.