Fennel oil is obtained by steam distillation of the aerial parts of Foeniculum vulgare Mill. ssp. vulgare var. vulgare (bitter fennel). It is a colorless to pale yellow liquid with a camphoraceous, sweet–spicy odor and a slightly bittersweet camphoraceous taste, d2020 0.944–0.973; n20D 1.514–1.538; α20D +11 ° to +29 °. The main constituents are monoterpene hydrocarbons such as ??-phellandrene (0–8.5%) and limonene (1–6%), fenchone (10–25%), estragole (1–6%), and (E)-anethole (50–78%). With increasing maturity of the fruits, the content of monoterpenes decreases. The ripe fruits yield an oil with 50–70% anethole and 5–25% fenchone. In contrast, the oil of the ripe fruits of sweet fennel (F. vulgare Mill. ssp. vulgare var. dulce) contains less than 5% fenchone and more than 75% anethole. Fennel oil is produced mainly in Hungary, Tasmania, North Africa, and India in a quantity of few 10 t/yr. In total. It is used in flavoring oral care products and alcoholic beverages (anise liqueurs).