Botanical name: Foeniculum vulgare
© Steven Foster
Parts used and where grown
The fennel plant came originally from Europe, where it is still grown. Fennel is also
cultivated in many parts of North America, Asia, and Egypt. Fennel seeds are used in herbal
medicine.
Fennel has been used in
connection with the following conditions (refer to the individual
health concern for complete information):
Historical or traditional use (may
or may not be supported by scientific studies)
According to the Greek legend of Prometheus, fennel was thought to have bestowed
immortality.1 Fennel seeds are a common cooking spice, particularly for use with fish. After meals, they are used in several
cultures to prevent gas and upset stomach.2 Fennel has also been used as a remedy
for cough and colic in infants.
Active constituents
The major constituents, which include the terpenoid anethole, are found in the volatile
oil. Anethole and other terpenoids inhibit spasms in smooth muscles,3 such as those
in the intestinal tract, and this is thought to contribute to fennel’s use as a
carminative (gas-relieving and gastrointestinal tract cramp-relieving agent). Related
compounds to anethole may have mild estrogenic actions, although this has not been proven in
humans. Fennel is also thought to possess diuretic (increase in urine production), choleretic
(increase in production of bile), pain-reducing, fever-reducing, and anti-microbial
actions.4 Fennel was formerly an official drug in the United States and was listed
as being used for indigestion.5
How much is usually taken?
The German Commission E monograph recommends 1–1 1/2 teaspoons (5–7 grams) of
seeds per day.6 To make a tea, boil 1/2 teaspoon (2–3 grams) of crushed seeds
per 1 cup (250 ml) of water for ten to fifteen minutes, keeping the pot covered during the
process. Cool, strain, and then drink three cups (750 ml) per day. As a tincture, 1–2
teaspoons (5–10 ml) can be taken three times per day between meals.
Are there any side effects or interactions?
No significant adverse effects have been reported. However, in rare cases fennel can cause
allergic reactions of the skin and respiratory tract.7 Anyone with an
estrogen-dependent cancer (e.g., some breast cancer patients) should avoid fennel in large
quantities until the significance of its estrogen-like activity is clarified.
Are there any drug
interactions?
Certain medicines may interact with fennel. Refer to drug interactions for a list of those medicines.
References:1. Duke JA. CRC Handbook of Medicinal Herbs. Boca Raton, FL: CRC
Press, 1985, 145–6.
2. Mills SY. Out of the Earth: The Essential Book of Herbal
Medicine. Middlesex, UK: Viking Arkana, 1991, 424–6.
3. Forster HB, Niklas H, Lutz S. Antispasmodic effects of some medicinal
plants. Plant Med 1980;40:303–19.
4. Tanira MOM, Shah AH, Mohsin A, et al. Pharmacological and
toxicological investigations on Foeniculum vulgare dried fruit extract in
experimental animals. Phytother Res 1996;10:33–6.
5. Hare HA, Caspari C, Rusby HH. The National Standard
Dispensatory. Philadelphia: Lea & Febiger, 1916, 63, 1129.
6. Blumenthal M, Busse WR, Goldberg A, et al. (eds). The Complete
Commission E Monographs: Therapeutic Guide to Herbal Medicines. Boston, MA: Integrative
Medicine Communications, 1998, 128–9.
7. Blumenthal M, Busse WR, Goldberg A, et al. (eds). The Complete
Commission E Monographs: Therapeutic Guide to Herbal Medicines. Boston, MA: Integrative
Medicine Communications, 1998, 128–9.