Fennel (Foeniculum vulgare)

Fennel (Foeniculum vulgare), also known as F. officinale, is a member of the Umbelliferae (Apiaceae) or carrot family, along with dill (Anethum graveolens), caraway (Carum carvi), and anise (Pimpinella anisum). Fennel has a thick, spindle-shaped taproot that produces a pithy, smooth or finely-fluted round stem that may reach to 6 ft (1.8 m) in height.

The finely divided leaves, with numerous thread-like segments, grow from a sheath surrounding the stalk at the base of the leaf stem. The delicate, blue-green filiform leaf segments have a pungent scent, somewhat similar to licorice, and an aniselike flavor. This characteristic is due to the presence of the phytochemical anethol, also a primary constituent of anise oil. Fennel’s tiny yellow flowers form in large, compound umbells. The blossoms are frequently visited by bees, wasps, and other insects, and fennel leaf is a favorite food of the swallowtail-butterfly.

This perennial native of the Mediterranean is called marathon in Greece, a name derived from the word maraino, meaning to grow thin. Fennel was recommended as an herb for weight reduction, “to make people more lean that are too fat,” according to the seventeenth century herbalist and astrologer Nicholas Culpeper. He considered fennel to be an herb of Mercury, under the sign of Virgo.

In Chinese and Hindu cultures fennel was ingested to speed the elimination of poisons from the system, particularly after snakebite and scorpion stings. As one of the ancient Saxon people’s nine sacred herbs, fennel was credited with the power to cure what were then believed to be the nine causes of disease.

Fennel was also valued as a magic herb. In the Middle Ages it was draped over doorways on Midsummer’s Eve to protect the household from evil spirits. As an added measure of protection, the tiny seeds were stuffed into keyholes to keep ghosts from entering the room.

Fennel was introduced to North America by Spanish missionaries for cultivation in their medicinal gardens. Fennel escaped cultivation from the mission gardens, and is now known in California as wild anise. English settlers brought the herb with them to the New England colonies where it became part of their kitchen gardens.

In Puritan folk medicine fennel was taken as a digestive aid. The herb is still found growing on the sites of these early English settlements. This attractive, aromatic and sun-loving herb thrives on roadsides, embankments, sea cliffs, and in dry, stony fields.

There are several different species and varieties of fennel that may be annual, biennial, or perennial. F. vulgare var. dulce, known as sweet fennel, or finocchio, is cultivated for the fleshy basal stalks. The stalks may be eaten fresh, like celery, or boiled and baked as a vegetable. This delicacy is known in Italy as carosella. Fennel has naturalized in most temperate areas of the world, and is extensively cultivated for medicinal, ornamental, and culinary uses.

Fennel (Foeniculum vulgare) illustration
Fennel (Foeniculum vulgare) illustration

General use

The seeds, leaves, and roots of fennel are safe and edible. The essential oil, extracted from the seeds, is toxic even in small amounts. Fennel has been widely used in culinary and medicinal preparations for centuries. The herb acts as a carminative, and was traditionally employed as a digestive aid and remedy for flatulence.

An infusion or decoction of the dried seeds is antispasmodic and will ease stomach pains and speed up the digestion of fatty foods. Fennel is a proven remedy for colic in infants, and is safe when administered as a mild infusion of the leaf and seed. It is also used for coughs and colds. Fennel exerts a calming influence on the bronchial tissues.

The seeds contain large amounts of the phytochemical alpha-pinene, which acts as an expectorant and helps to loosen phlegm in the lungs. An eyewash, prepared from a decoction of the crushed seeds, is said to improve eyesight and reduce irritation and eyestrain. Fennel has a long history of use as a galactagogue. The seed, when boiled in barley water, acts to increase the flow of breast milk in nursing mothers.

A poultice of the herb may be helpful to relieve swelling of the breasts during lactation. A leaf and seed tea has been used to expel hookworm and kill intestinal bacteria. Fennel has also been used to promote appetite. The entire herb is used in culinary dishes, and the fleshy sheaths surrounding the base of the leaf stems are a staple in Italian cuisine.

The foliage, known as fennel weed, is used to flavor eggs, fish, stews, and vegetables. The root is sometimes grated fresh and added to salads. The licorice-flavored seeds are traditionally served after meals in India to cleanse the breath. The flowers produce a yellow tint and the leaves a light brown hue as a natural dye for wool fabrics.

Fennel seed contains volatile oil, most of which is identified as trans-anethole, with a much smaller amount identified as fenchone. Other components of the essential oil include limonene, camphene, and alpha-pinene.


Harvest fennel leaf from time to time throughout the growing season. Use the fresh leaf when possible as the herb may lose much of the flavor when dried. The leaves may also be frozen for later use. Harvest the seeds in autumn. Seeds are fully ripe just as the color fades and the seed-bearing umbells turn from yellow-green to a light brown.

Fennel seeds
Fennel seeds

Cut the brown umbell from the stalk and place it in a paper bag to dry in a warm room. Shake the dried seeds from the umbell and store them in tightly sealed, clearly labelled, dark-glass containers. Harvest the root late in the fall at the same time the stems are harvested as a vegetable. The root is generally less medicinally potent than the seeds.

Seed infusion: Crush 1 tsp–1 tbsp of the dried seed, add to 1 cup of unchlorinated water, fresh milk, or barley water, in a non-metallic pot. Bring to a boil; then steep, covered, for about 10 minutes. A standard dosage of the tea is two to three cups per day.

Root decoction: Add one ounce of the clean, thinlysliced dry root, or 2 oz of thinly-sliced fresh root, to 1 pt of unchlorinated water in a non-metallic pot. Bring to a boil and simmer for about 10 minutes. Strain and cover. A decoction may be refrigerated for up to two days and retain its healing qualities.

Tincture: Combine half a cup of dried fennel seeds with 1 pt of brandy or vodka in a glass container. Seal the container with an airtight lid. Leave to macerate in a darkened place for two weeks. Shake daily. Strain the mixture through a cheesecloth or muslin bag and pour into a dark bottle for storage up to two years. Dosage is 2–4 ml of the tincture two times a day.


Pregnant women should not use the herb, seeds, tincture, or essential oil of fennel in medicinal remedies. Small amounts used as a culinary spice are considered safe. In large doses fennel acts as a uterine stimulant. The essential oil of fennel is toxic in doses as small as 5 ml, and may cause skin irritation, vomiting, seizure, and respiratory problems. The volatile oil should not be ingested. The herb and seed oil may cause contact dermatitis in sensitive individuals.