Fennel: Overview

Alternative names: Common Fennel, Sweet Fennel or Bitter Fennel, Carosella, Florence Fennel, Finocchio, Garden Fennel, Large Fennel, Wild Fennel, F. officinale, Anethum foeniculum.

Fennel is native to the Mediterranean region, but is now cultivated worldwide.  It is an aromatic perennial that grows to about five feet (~2metres) in height, having dark green, feathery leaves, umbels of yellow flowers, and small, ridged, oval-shaped seeds, which are gathered in the autumn.

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The tall stalk looks like celery and is often consumed as vegetables, while the leaves and seeds are used to flavor foods.  Although the taste and aroma of fennel are sometimes mistaken for anise or licorice, the plant is actually related to caraway.

History; Source

The name "foeniculum" is from the Latin word for "fragrant hay."  Fennel is one of the oldest cultivated plants and much valued by the Romans.  Warriors took it to keep good health, while their ladies took it to stave off obesity.  Fennel was also in great demand during the Middle Ages.  The rich added the seed to fish and vegetable dishes, while the poor reserved it as an appetite suppressant to be eaten on fasting days.  In medieval times, the seeds were chewed to stop gastric rumblings during church services.  The plant was introduced to North America by Spanish priests and the English brought it to their early settlements in Virginia.  All parts of the plant have been used for flavorings, and the stalks have been eaten as a vegetable.

All parts of the plant are aromatic (seeds, essential oil, root).  Although the root is sometimes used medicinally, it is not as effective as the seeds and used mainly as a vegetable.  The seeds have a taste resembling that of anise and are used for making herbal tea, but the roots are especially beneficial when treating urinary tract infection.

Function; Why it is Recommended

Key components are volatile oil (8% consisting of up to 80% anethole, 18-22% fenchone and methyl chavicol), flavonoids, coumarins (including bergapten), and sterols.  Fenchone is a pungent gas.  Estragole is a phytoestrogen that mildly mimics the female hormone, estrogen, and was once used to produce a synthetic version used in the treatment of bloating, breast tenderness, other PMS symptoms, and cramping.  Fennel seed extracts have proven to calm muscle spasms by reducing smooth muscle contractions.  Studies indicate that substances in fennel can reduce airway congestion by thinning and loosening phlegm, which tends to support the addition of fennel in numerous European cough remedies.

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Fennel is claimed to be an antidote to poisonous herbs, mushrooms and snakebites.  It also has been used for the treatment of gastroenteritis, indigestion, to stimulate lactation and as an expectorant and to stimulate menstrual flow.  Tea made from crushed fennel seeds has been used as an eyewash for conjunctivitis.

As an herbal medicine, fennel is reputed to increase milk secretion, promote menstruation, facilitate birth, ease the male climacteric, and increase the libido.  These supposed properties led to research on fennel for the development of synthetic estrogens during the 1930s.

An infusion from the seeds makes a good gargle for sore throats or used as a mild expectorant.

A syrup made from an infusion is given for colic and teething pain in babies.  A decoction from the seeds is used in Chinese medicine to relieve abdominal pains, colic, and stomach chills.

The primary use for the herb is for digestive upsets and settling stomach pain while stimulating the appetite.  The seeds are soothing for the digestive system.  Essential oil is used for digestive and relaxing needs.  Tinctures from the seeds are used for digestive problems.

Mouthwash and gargles are made from infusions for gum disorders, loose teeth, laryngitis, and sore throats.

Chest rubs are made from the essential oil and combined with eucalyptus and a neutral oil for upper respiratory congestion.  Decoctions from the roots are prescribed for such urinary problems as kidney stones or such disorders associated with high uric acid content as gout.

It aids in the treatment of kidney stones.  When combined with such urinary antiseptics as uva ursi, it makes an effective treatment for cystitis.  In Chinese medicine, the seeds (hui xiang) are thought to be a toner for the spleen and kidneys, and are also used in urinary and reproductive disharmonies.

Other benefits of Fennel:

  • improving digestion
  • long history of use for weight loss and warding off ageing
  • detoxifier
  • boosting metabolism
  • stomach cramps
  • heartburn
  • morning sickness
  • bloating
  • flushing the kidneys
  • after chemotherapy and radiation.

Research reveals no clinical data regarding the use of fennel as a stimulant to promote lactation and menstruation, although animal studies indicate a possible estrogenic effect.  None of the other health claims have much, if any, clinical research to support them.


Fennel seed and fennel seed oil have been used as stimulant and carminative agents in doses of 5-7gm and 0.1-0.6 ml, respectively.

Side-Effects; Counter-Indicators and Warnings

Fennel may cause photodermatitis, contact dermatitis, and cross reactions.  The oil may induce hallucinations, seizures, etc.

Fennel oil was found to be genotoxic in the Bacillus subtilis DNA-repair test.  Estragole, present in the volatile oil, has been shown to cause tumors in animals.

Therapeutic quantities should not be used during pregnancy.  There are documented adverse effects during pregnancy or while nursing.  May cause contact dermatitis and/or photosensitivity.  Ingesting even small amounts of undiluted fennel oil can cause nausea, vomiting, and seizures.  Those with hepatitis, cirrhosis, or other liver disorders are advised not to take fennel.

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Fennel can help with the following:


IBS (Irritable Bowel Syndrome)

Other herbs and products used with varying success include: fennel, dandelion, skullcap, licorice, peppermint, valerian, slippery elm, cranberry, glutamine, MSM, magnesium, and gamma-oryzanol.

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