Foeniculum vulgare, commonly known as fennel, has been used as an herbal remedy since ancient times. The most commonly used parts of fennel plants are the leaves and fruits, which are often incorrectly called seeds, due to their seedlike appearance. Fennel is an aromatic and flavorful herb, making it a popular additive in cooking. The seedlike fruit has been used for a wide variety of medicinal purposes, including increasing milk production in lactating women.
Fennel is a perennial plant indigenous to the lands surrounding the Mediterranean Sea. In ancient Greece, fennel was originally named "marathon," although it was later Latinized to “feniculum” because it has a haylike appearance when dried. The Latin term was reduced to “fenol” in Old English and then “fenel” in Middle English before its modern spelling. The ancient Greeks used fennel seeds to increase lactation in breastfeeding women. The ancient Romans regarded fennel more as an herbal remedy to promote healthy vision and improve eyesight, as explained in “The Essential Book of Herbal Medicine.” In India, traditional uses for fennel also include enhancing digestion.
Fennel seeds contain anethole, which is considered a phytoestrogen. Phytoestrogens mimic the properties of the hormone estrogen, which is normally involved in the growth of the mammary glands and increased secretion of milk in women. Estrogen is also responsible for female secondary sexual characteristics. Anecdotal evidence suggests that moderate to high doses of anethole-rich fennel may promote growth of breast tissue, increase lactation volume and improve the quality of breast milk, although scientific research on people is lacking according to “Medical Herbalism.” Some nonlactating women use fennel seeds to simply enlarge their breasts, although no evidence supports such practice. Fennel seeds are a good source of vitamin C, which may account for some of its medicinal benefits.
Traditionally fennel seeds are soaked in hot water and made into an herbal infusion, which is then sweetened by honey or other natural sweeteners. Thick syrup can be made from fennel juice and its seeds, which is considered effective at reducing chronic coughs. Fennel seeds can be dried and eaten raw or ground into powder and taken as capsules. The taste of fennel seeds is similar to licorice or anise. According to “The Way of Ayurvedic Herbs,” breastfeeding women may stimulate breast milk production by using topical fennel oil applications or moderate amounts of fennel tea. Up to 7 g daily of fennel seed is considered safe for adults, although its toxicity is not well established.
Oil made from fennel seed is often not recommended for internal consumption because of potential toxicity and premature breast development from excessive use. In regards to toxicity, a single case was reported of fennel tea ingested by a breastfeeding mother that led to neurotoxicity within her newborn child, according to a 1994 article published in the journal “Acta Paediatrica.” The infant did not die or suffer permanent nerve damage.