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Fennel

Uses

Botanical names:
Foeniculum vulgare

Parts Used & 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.

What Are Star Ratings?

Our proprietary “Star-Rating” system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.

For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.

3 Stars Reliable and relatively consistent scientific data showing a substantial health benefit.

2 Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.

1 Star For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.

This supplement has been used in connection with the following health conditions:

Used for Why
2 Stars
Colic
1 to 4 teaspoons of a water emulsion of 0.1% fennel seed oil, up to four times per day
In one study, supplementing with fennel seed oil relieved colic in 65% of cases, compared with 24% of infants receiving a placebo.

In a double-blind study of infants with colic, supplementation with an emulsion of fennel seed oil relieved colic in 65% of cases, compared with 24% of infants receiving a placebo, a statistically significant difference.3 The amount used was 1 to 4 teaspoons, up to four times per day, of a water emulsion of 0.1% fennel seed oil.

2 Stars
Colic (Chamomile, Lemon Balm, Licorice, Vervain)
1/2 cup (118 ml) of tea up to three times daily
A soothing tea made from chamomile, vervain, licorice, fennel, and lemon balm has been shown to relieve colic more effectively than placebo.

Carminatives are a class of herbs commonly used for infants with colic. These herbs tend to relax intestinal spasms.

Chamomile is a carminative with long history of use as a calming herb and may be used to ease intestinal cramping in colicky infants. A soothing tea made from chamomile, vervain, licorice, fennel, and lemon balm has been shown to relieve colic more effectively than placebo.4 In this study, approximately 1/2 cup (150 ml) of tea was given during each colic episode up to a maximum of three times per day.

2 Stars
Indigestion, Heartburn, and Low Stomach Acidity
1/2 tsp (2 to 3 grams) of ground or crushed seeds three times daily, taken directly or as tea
Studies have found that a combination of peppermint, caraway, and fennel is useful in reducing gas and cramping in people with indigestion.

Carminatives (also called aromatic digestive tonics or aromatic bitters) may be used to relieve symptoms of indigestion, particularly when there is excessive gas. It is believed that carminative agents work, at least in part, by relieving spasms in the intestinal tract.5

Among the most notable and well-studied carminatives are peppermint, fennel, and caraway. Double-blind trials have shown that combinations of peppermint and caraway oil and a combination of peppermint, fennel, caraway, and wormwood have been found to reduce gas and cramping in people with indigestion.6 , 7 , 8 Generally, 3–5 drops of natural essential oils or 3–5 ml of tincture of any of these herbs, taken in water two to three times per day before meals, can be helpful. Alternately, a tea can be made by grinding 2–3 teaspoons of the seeds of fennel or caraway or the leaves of peppermint, and then simmering them in a cup of water (covered) for ten minutes. Drink three or more cups per day just after meals.

2 Stars
Irritable Bowel Syndrome (Caraway Seed, Peppermint, Wormwood)
Refer to label instructions
A combination of peppermint, caraway seeds, fennel seeds, and wormwood was reported to be an effective treatment for upper abdominal complaints in one trial.

Whole peppermint leaf is often used either alone or in combination with other herbs to treat abdominal discomfort and mild cramping that accompany IBS. The combination of peppermint, caraway seeds, fennel seeds, and wormwood was reported to be an effective treatment for upper abdominal complaints in a double-blind trial.9

1 Star
Irritable Bowel Syndrome
Refer to label instructions
A combination of peppermint, caraway seeds, fennel seeds, and wormwood was reported to be an effective treatment for upper abdominal complaints in one trial.

Whole peppermint leaf is often used either alone or in combination with other herbs to treat abdominal discomfort and mild cramping that accompany IBS. The combination of peppermint, caraway seeds, fennel seeds, and wormwood was reported to be an effective treatment for upper abdominal complaints in a double-blind trial.10

Traditional Use (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.

How It Works

Botanical names:
Foeniculum vulgare

How It Works

The major constituents, which include the terpenoid anethole, are found in the volatile oil. Anethole and other terpenoids inhibit spasms in smooth muscles,11 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.12 Fennel was formerly an official drug in the United States and was listed as being used for indigestion.13

How to Use It

The German Commission E monograph recommends 1–1 1/2 teaspoons (5–7 grams) of seeds per day.14 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.

Interactions

Botanical names:
Foeniculum vulgare

Interactions with Supplements, Foods, & Other Compounds

At the time of writing, there were no well-known supplement or food interactions with this supplement.

Interactions with Medicines

Certain medicines interact with this supplement.

Types of interactions: Beneficial Adverse Check

Replenish Depleted Nutrients

  • none

Reduce Side Effects

  • none

Support Medicine

  • none

Reduces Effectiveness

  • Ciprofloxacin

    Preliminary research in animals has shown that fennel (Foeniculum vulgare) may reduce the absorption of ciprofloxacin.15 This interaction may be due to the rich mineral content of the herb; it has not yet been reported in humans. People taking ciprofloxacin should avoid supplementing with fennel-containing products until more is known.

Potential Negative Interaction

  • none

Explanation Required

  • none

The Drug-Nutrient Interactions table may not include every possible interaction. Taking medicines with meals, on an empty stomach, or with alcohol may influence their effects. For details, refer to the manufacturers’ package information as these are not covered in this table. If you take medications, always discuss the potential risks and benefits of adding a supplement with your doctor or pharmacist.

Side Effects

Botanical names:
Foeniculum vulgare

Side Effects

No significant adverse effects have been reported. However, in rare cases fennel can cause allergic reactions of the skin and respiratory tract.16 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.

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. Alexandrovich I, Rakovitskaya O, Kolmo E, et al. The effect of fennel (Foeniculum Vulgare) seed oil emulsion in infantile colic: a randomized, placebo-controlled study. Altern Ther Health Med 2003;9:58–61.

4. Weizman Z, Alkrinawi S, Goldfarb D, et al. Efficacy of herbal tea preparation in infantile colic. J Pediatr 1993;122:650–2.

5. Forster HB, Niklas H, Lutz S. Antispasmodic effects of some medicinal plants. Planta Med 1980;40:303–19.

6. May B, Kuntz HD, Kieser M, Kohler S. Efficacy of a fixed peppermint/caraway oil combination in non-ulcer dyspepsia. Arzneimittelforschung 1996;46:1149–53.

7. Westphal J, Hörning M, Leonhardt K. Phytotherapy in functional upper abdominal complaints. Results of a clinical study with a preparation of several plants. Phytomedicine 1996;2:285–91.

8. Madisch A, Heydenreich CJ, Wieland V, et al. Treatment of functional dyspepsia with a fixed peppermint oil and caraway oil combination as compared to cisapride. Arzneimittelforschung 1999;49;925–32.

9. Westphal J, Hörning M, Leonhardt K. Phytotherapy in functional abdominal complaints: Results of a clinical study with a preparation of several plants. Phytomedicine 1996;2:285–91.

10. Westphal J, Hörning M, Leonhardt K. Phytotherapy in functional abdominal complaints: Results of a clinical study with a preparation of several plants. Phytomedicine 1996;2:285–91.

11. Forster HB, Niklas H, Lutz S. Antispasmodic effects of some medicinal plants. Plant Med 1980;40:303–19.

12. 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.

13. Hare HA, Caspari C, Rusby HH. The National Standard Dispensatory. Philadelphia: Lea & Febiger, 1916, 63, 1129.

14. 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.

15. Zhu M, Wong PY, Li RC. Effect of oral administration of fennel (Foeniculum vulgare) on ciprofloxacin absorption and disposition in the rat. J Pharm Pharmacol 1999;51:1391–6.

16. 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.

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