The following monograph on fennel is an excerpt from the forthcoming book The Essential Guide to Western Botanical Medicine.
Botanical Name(s): Foeniculum vulgare, F. vulgare var. ruburum, F. vulgare var. dulce, F. vulgare var. vulgare, F. vulgare var. azoricum
Common Name(s): Fennel, bronze fennel,bitter fennel, sweet fennel, fenkel, hinojo (Spanish), finocchio (Italian), shatapushpa (Sanskrit), xiao hui xiang (Chinese)
Family Name: Apiaceae (Umbelliferae) 
MEDICINAL USES
Fennel seed is one of the most effective digestive aids, having carminative, smooth muscle antispasmodic, and stomachic properties. It is highly beneficial to reduce digestive cramping, gas, and bloating. The volatile oils contained in the seed stimulate the mucus membranes in the digestive tract, encouraging motility and peristalsis. The aromatic oils also exert smooth muscle antispasmodic and carminative actions. The seed tincture or tea is effective for treating intestinal spasms that result from conditions such as irritable bowel syndrome, ulcerative colitis, Crohn’s disease, leaky gut syndrome, Celiac’s disease, and intestinal candidiasis. Fennel’s properties pass through breast milk, reducing infant colic. Fennel seed has anti-nauseant properties, aiding recovery from stomach flu, food poisoning, digestive infections, and hangovers. It anesthetizes pain resulting from a hiatal hernia and indigestion. Fennel decongests the liver and is a useful adjunct for conditions arising from liver stagnation.
Fennel seed complements cathartic laxative and purgative compounds, as well as digestive bitter and cholagogue formulas. It reduces griping caused by the more potent purgative and laxative herbs used for treating constipation. It also prevents cramping that result from cooling bitter herbs that stimulate excretion of bile from the gall bladder, such as Cheladonium (celandine), Cynara (artichoke leaf), Gentiana (gentian), or Berberis (Oregon grape). Fennel seed tincture can be combined to modify the harshness of cooling, bitter, antimicrobial herbs when treating digestive infections such as stomach flu, food poisoning, and giardia.
The seeds have moderate expectorant and antitussive properties; however, the antitussive actions are not as potent as anise, fennel’s cousin. While anise seed is preferred for treating respiratory conditions, fennel can be incorporated into compounds for treating dry, hacking coughs, bronchitis, pneumonia, and asthma.
Fennel seed has mild diuretic properties that reduce edema. This is likely one of the reasons it is included in weight loss formulas, though it was also used historically as an appetite suppressant.
Fennel seed has galactogogue actions, increasing the supply of breast milk. Additionally, the carminative properties pass through the breast milk and may be used to reduce infant colic.
A decoction of fennel seed, strained through a fine cloth or paper filter, may be used as eyewash for sore, strained, or bloodshot eyes, or with other anti-infective agents for conjunctivitis.
Fennel is used as a flavoring agent and a harmonizer in blends; however, some individuals despise the “licorice-like” flavor. To encourage compliance, it’s important to assess whether a patient enjoys the taste before including it in herbal compounds.
Fennel Essential Oil
The aroma of fennel seed essential oil is revitalizing, energizing, and helps to increase self motivation. It’s useful to reduce sluggishness and lethargy, and to improve energy levels. Incorporated into facial creams for mature skin, it refines the complexion. Fennel essential oil has long been included in soaps, detergents, creams, lotions, and perfumes.
The essential oil or spirits may be used internally with caution, in a one- to two-drop dose range. It has spasmolytic and mucolytic actions for the digestive and respiratory tract. It also reduces nausea, gas, and bloating.
CONTRAINDICATIONS
Fennel seeds are very gentle, but there are rare cases in which fennel causes allergic reactions in the skin and respiratory tract. Fennel seeds are not considered dangerous; however, the essential oil can be toxic in high doses.
Fennel seed essential oil use should be avoided during pregnancy. It has been reported to have estrogen-like activities; therefore, internal consumption of the essential oil should be avoided by individuals with estrogen-sensitive conditions (reproductive cancers, tumors, or cysts). Internal use of the essential oil should be avoided by lactating women and children under the age of ten. The essential oil can overexcite the nervous system, and may cause convulsions in sensitive individuals. Avoid use with existing nervous system conditions such as epilepsy, Parkinson’s, or multiple sclerosis. An overdose of the essential oil can cause skin irritation, allergy, nausea, vomiting, seizures, or pulmonary edema.
DESCRIPTION
Part(s) Used:The fruits (seeds) are used as medicine. The bulb and leaves are used for culinary purposes
Habitat and Locality: Fennel is native to the Mediterranean, and is cultivated throughout Europe, Asia, India, Australia, and North America. The herb is a biennial or perennial grown in temperate climates, and an annual when grown in colder climates. Italian fishermen were reputed to introduce fennel to California where it naturalized (or became an invasive weed). Fennel has spread through the coast of California and into Oregon, growing in dense colonies on roadsides and disturbed sites. Once planted, it is difficult to eradicate.
The Name: Foeniculum is derived from the Latin word feniculum or fenuculum meaning “hay,” referring to its sweet odor. The epithet vulgare originates from the Latin word vulgaris meaning “of or pertaining to the common people, common, or vulgar”.1 During the Middle Ages, Feoniculum was corrupted to fanculum, which evolved into the common name fenkel. The ancient Greeks named the plant Marathron, derived from mariano, meaning “to grow thin.” This refers to the plant’s use as an appetite suppressant for weight loss or times of famine.2 The Sanskrit name is shatapushpa whichtranslates as “what possesses a hundred flowers”.3 The following Latin names correspond with the common names: Foeniculum vulgare (common or wild fennel), F. vulgare var. ruburum (bronze fennel), F. vulgare var. dulce (sweet fennel), F. vulgare var. vulgare (bitter fennel), and F. vulgare var. azoricum (finnochio or Florence fennel).
Historical Uses: Fennel has been employed as food and medicine throughout the world and is used today in India, China, Europe, and North America. Ancient Romans cultivated fennel for its succulent edible shoots and fruits. Pliny, a Roman naturalist and historian, listed medicinal uses for fennel. Ancient Greeks and Romans believed fennel bestowed strength, courage, and longevity. In Medieval times, fennel and St. Johnswort were hung over doors on Midsummer’s Eve to ward off evil spirits and prevent witchcraft. Emperor Charlemagne (742-814 A.D) was credited for introducing fennel cultivation to Central and Northern Europe, where it was grown on his imperial farms. Fennel seeds were utilized as medicine for conditions of the lungs, kidneys, digestion, liver, spleen, and gallbladder. In Europe, fennel water, also known as la gripe water, was a household remedy for infant colic. Fennel leaves or seeds were boiled in barley water and consumed by nursing mothers to increase the flow of breast milk and impart strength to the infant. Fennel seeds were added to purgatives to prevent griping pain. Fennel seeds are still used as an ingredient in cordials and liqueurs; they are consumed as an aperitif or digestif. It was a common practice in Europe to boil fish with fennel leaves to reduce the odor and improve digestion of fatty fish. Fennel was believed to restore vision and strengthen the eyes. Water-based preparations of fennel were used to treat eye infections. In Traditional Chinese Medicine, fennel was used as a powder poultice for slowly healing snakebites. Powdered fennel sprinkled throughout kennels and stables was said to ward off fleas.2(p293-297),4,5
Anethole structure
Constituents: Fennel seed contains: volatile oils (anethole, d-fenchone, methyl chavicol, anisic aldehyde, anisic acid, 
d-α-pinene, diterpene); fixed oil (petroselinic acid, oleic acid, linoleic acid, tocopherols); phenolic acids (caffeic acid); flavonoids (quercetin-3-glucuronide, rutin, isoquercetin, quercetin-3-arabinoside, kaempferol-3-glucuronide); saponins (stigmasterol); coumarin (umbelliferone); protein; sugar; as well as vitamins and minerals (listed below).4(p241),6,7
The essential oil of fennel contains volatile oils (transanethole, fenchone, estragole, limonene, camphene, and α-pinene); monoterpene hydrocarbons (β-pinene, α-thujene, α-fenchene, 3-carene, sabinene, α-phellandrine; myrcene, α- and β-terpinene, cis- and trans-ocimenes, terpinolene, and p-cymene); fenchyl alcohol; anisaldahyde; anisic acid; trans-1,8-terpin; myristicin; and apiole (the latter two are present only in sweet fennel).4(p241),8
Nutritional Properties: Fennel seed contains calcium, chromium cobalt, fiber, fat, iron, magnesium, manganese, niacin, phosphorus, potassium, protein, riboflavin, selenium, silicon, sodium, thiamine, tin, vitamin A and C, and zinc.6(p89) Fennel leaf and bulb contains vitamins A and C, calcium, iron, potassium, phosphorus, and protein.9
Medicinal Properties:Aromatic, carminative, stomachic, antispasmodic, antitussive, expectorant, diuretic, galactagogue, and harmonizer.
Energetic Properties: Warm, sweet, bitter, and acrid. However, Ayurvedic practitioner Vasant Lad lists the seeds as slightly cooling.3
METHODS OF PREPARATION AND DOSAGE
Tincture: Fresh seed [1:2, 95% alcohol] or dry seed [1:5, 60% alcohol]; consume 15-60 drops, up to three times a day.
Glycerite: Fresh [1:2,50% glycerin and 50% alcohol];consume 15-60 drops, up to three times a day.
Acetum Extract: Fresh [1:2, 95% organic apple cider vinegar] or dry seed [1:5, organic apple cider vinegar]; consume 30-90 drops, up to three times a day.
Capsules: Consume two “00” capsules, up to three times per day.
Tea: The seeds can be prepared as a standard infusion, cold infusion, or a decoction. Consume up to 32 ounces per day of the tea. Fennel decoction has a richer flavor and creamier consistency than the infusion. A fennel milk decoction can be prepared by simmering the crushed seeds in milk for 10 minutes on a low temperature.
Honey and Syrups: One option is to make infused syrup. Decoct fennel seeds to half the original volume, strain the seeds, and sweeten to taste with honey, maple syrup, or simple syrup. Consume one teaspoon, up to four times a day. Store the syrup in the fridge for up to one month. Another option is to add one to two drops of the organic essential oil to a teaspoon of honey or simple syrup, and mix thoroughly. Consume or add to a cup of hot water or herbal tea.
Culinary Uses: The seeds and essential oil have long been used as a flavoring agent in beverages, condiments, and foods. Add the seeds to breads, cookies, and other baked goods. Prepare a delicious digestive chew by combining fennel seed, anise seed, cardamom seed, orange peel, and chopped, crystalized ginger. Or consume the seeds following a meal to enhance digestion and as a breath freshening agent. Dry roast the seeds to enhance the aromatics.
The finely chopped fresh leaves are a lovely addition to salads, root vegetable dishes, vinaigrettes, marinades, soups, herbal butters, cream sauce, fish or chicken dishes. The tender bulbs are edible in the fall of the first year, but they can become very fibrous after that season. Fennel bulbs are delicious sautéed with a little butter, cream, sherry, onions, salt, and pepper.
Preparations Using the Essential Oil: Fennel spirits can be made by adding one part by volume of fennel essential oil to ten parts by volume of organic alcohol. Consume one to two drops of the spirits, one to three times a day. Place one to two drops of fennel seed essential oil on a sugar cube or in one teaspoon of honey; dissolve into one cup of warm water and drink. Place 2-4 drops of the essential oil into one teaspoon of base oil and massage into the belly (for adults); for children, only use one drop diluted in base oil and massage into the belly.
WORKS CITED
- Fennel. Online Etymology Dictionary Web site. http://www.etymonline.com/index.php?term=fennel&allowed_in_frame=0. Accessed July 1, 2013.
- Grieve M. A Modern Herbal. Great Britain: Jonathan Cape Ltd.; 1931:293-295.
- Lad, V, Frawley D. The Yoga of Herbs. Twin Lakes, WI: Lotus Press; 1992:117.
- Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in
Food, Drugs, and Cosmetics. 2nd ed. Hoboken, NJ: A John Wiley & Sons, Inc.; 2003: 242. - Foster S, Johnson R. Desk Reference to Nature’s Medicine. Washington, D.C.: National Geographic Society; 2006: 166-167.
- Pedersen M. Nutritional Herbology: A Reference Guide to Herbs. Warsaw, IN: Wendell W. Whitman Company; 1998:90.
- Skenderi G. Herbal Vade Mecum. Rutherford, NJ: Herbacy Press; 2003:151.
- Willard T. Edible and Medicinal Plants of the Rocky Mountains and Neighboring Territories. Calgary, AB: Wild Rose College of Natural Healing; 1992:118.
- Foster S. Herbal Renaissance. Layton, UT: Peregrine Smith Books; 1993:92.