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Fennel (Foeniculum vulgare Mill.)

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Also listed as: Foeniculum vulgare Mill.
Related terms
Background
Evidencetable
Tradition
Dosing
Safety
Interactions
Attribution
Bibliography

Related Terms
  • Adas, adas pedas, anason dulce, aneth doux, anis, Anethum foeniculum, Anthemis cotula (dog fennel), Apaiaceae (parsley family), aptechnyj ukrop, apteegitilliseemne, badesopu, badishep, bitter fennel, carosella, cay thi la, common fennel, edeskomeny, fenchel, fenheli parastie, fenhelis, fenicol, fenikel, fenkel, fenkhel, fenkoli, fenkolo, fennel honey syrup, fennel oil, fenneru, fennika, fennikel, fenouil, fenoun, fenykl, ferula communis (giant fennel), finocchio, finokio, florence fennel, Foeniculi antheroleum, Foeniculum capillaceum, Foeniculum officinale, Foeniculum vulgare, Fructus foeniculi, funcho, garden fennel, guamoori, haras, harilik apteegitill, hinojo, hoehyang, hoehyang-pul, hoi huong, hui xiang, jinten manis, kama, koper wloski, komorac, koper, koromac, large cummin, large fennel, lus an t'saiodh, madhurika, maduru, marac, maratho, mehul, mellet karee, merula obisnuita, mieloi, miur belar, molura, morach, moti saunf, mouri, paciolis, pak chi duanha, pan mohuri, paprastasis pankolis, pedda jilakarra, pennel, perunjiragam, phak si, phong karee, phytoestrogen, razianaj, razianeh, razyana, rezene, samit, samong-saba, saunf, shamaar, shamar, shamari, shamraa, shatpushpa, shoap, shoumar, shumar, siu wuih heung, sladki komarcek, sladkij ukrop, so-hoehyang, sohikirai, sombu, sonf, sopu, spice of the angels, sulpha, sweet cumin, sweet fennel, thian-klaep, tian hi xiang, tieu hoi huong, tihm wuih heung, uikyo, ukrop sladki, Umbilliferae (parsley family), venkel, wariari, wild fennel, wuih heung, xiao hui xiang, yira.
  • Note: Some languages do not differentiate between anise and fennel.

Background
  • Fennel is native to the Mediterranean region. For centuries, fennel fruits have been used as traditional herbal medicine in Europe and China. For the treatment of infants suffering from dyspeptic (indigestion) disorders, fennel tea is the remedy of first choice. Its administration as a carminative (digestive aid) is practiced in infant care in private homes and in maternity clinics where it is highly appreciated for its mild flavor and good tolerance.
  • There is evidence suggesting that fennel is effective in reducing infantile colic. Fennel has also been studied in human clinical trials for ACE inhibitor-induced cough, dysmenorrhea (painful menstruation), and ultraviolet protection, but additional research is merited in these areas.

Evidence Table

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. GRADE *


An emulsion of fennel seed oil and an herbal tea containing fennel have reduced infantile colic. Additional studies are warranted in order to confirm these findings.

B


Fennel fruit may be helpful in relieving cough (a side effect of angiotensin converting enzyme inhibitor [ACEI]). However, there is insufficient evidence to recommend for or against its use for ACEI-induced cough.

C


Fennel has been used to treat dysmenorrhea. Although preliminary study is promising, there is currently insufficient evidence to recommend for or against this use of fennel.

C


Topical fennel extract improved sun protection factor (SPF) and decreased UV-induced erythema (reddening of the skin) and demonstrated consistent inhibition of lipid peroxidation. However, results were not conclusive.

C
* Key to grades

A: Strong scientific evidence for this use
B: Good scientific evidence for this use
C: Unclear scientific evidence for this use
D: Fair scientific evidence for this use (it may not work)
F: Strong scientific evidence against this use (it likley does not work)


Tradition / Theory

The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.

  • Abdominal cramps, abortion (when used in combination), attention deficit hyperactivity disorder (ADHD), antibacterial, antifungal, antioxidant, bad breath, bone loss (inhibition of bone resorption), bronchitis, bust enhancer, cancer preventative (in combination with antioxidants), common cold / upper respiratory tract infection, cough, digestion, dyspepsia (upset stomach), eye disorders (improve eyesight), feeling of fullness, flatulence (gas), flavoring, flu, fragrance, galactagogue (stimulates milk production), gastrointestinal discomfort, intestinal cramps, labor and delivery (facilitates birth), libido, loss of appetite, promotes menstruation, prostate cancer, sedative, spastic colon (disorders of the GI tract), visual disturbances.

Dosing

Adults (over 18 years old)

  • There is no proven safe or effective dose of fennel. For angiotensin converting enzyme inhibitor-induced cough, 1-1.5 grams of fennel fruit has been used up to three times daily. Up to 4,600 micrograms has been studied for its antioxidant effects. For dysmenorrhea (painful menstruation), 25 drops of a 2% concentration of fennel fruit has been taken every four hours for five days.
  • Traditionally, numerous other doses and preparations have been used, in the form of tea, seed, tincture, oil or dry extract.

Children (under 18 years old)

  • There is no proven safe or effective dose of fennel in children. For infantile colic (ages of 2 to 12 weeks), a 0.1% fennel seed oil in a water emulsion and 0.4% polysorbate-80 has been studied for one week. Traditional dosing for upper respiratory tract catarrh (inflammation of mucous membranes) in children is 0.5 gram of the oil per kilogram. For ages 1 to 4 years, 3-6 grams has been used daily; for ages 4 to 10 years, 6-10 grams has been used daily.

Safety

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

  • Avoid in individuals with a known allergy or hypersensitivity to fennel or other members of the Apiaceae family including carrot, celery, and mugwort because of the chance of cross-sensitization. Oral allergy syndrome has been reported with the use of fennel in a woman. Allergic reactions affecting the skin such as atopic dermatitis and photosensitivity may occur in patients who consume fennel.

Side Effects and Warnings

  • Fennel is generally well tolerated. Allergic reactions, such as atopic dermatitis and photosensitivity, are the most common adverse effects but rarely occur. Fennel oil has generally recognized as safe (GRAS) status for food use in the United States. A maximum level of 0.119% is allowed in meat products.
  • Epileptic seizures have been reported with the use of fennel oil. Respiratory problems including bronchial asthma, hay fever, occupational rhinoconjunctivitis (inflammation of the lining of the nose and the mucous membrane that covers the front of the eye and lines the eyelids) and asthma have been reported in patients working with fennel seed.
  • Inhalation of essential oils, including fennel oil, resulted in 1.2-2.5-fold increase in relative sympathetic activity, representing low frequency amplitude of systolic blood pressure.
  • Use cautiously in diabetic patients. Fennel honey syrup is a source of carbohydrates.
  • Yersinia enterocolitica, a bacterial pathogen, has been isolated in the Umbelliferae family, which could pose a potential threat of infection if fennel is consumed fresh. Fennel preparations, other than fennel seed infusions and fennel honey, should be avoided in infants and toddlers.
  • The constituent, estragoel, is a procarcinogen (precursor of a cancer causing compound).

Pregnancy and Breastfeeding

  • Fennel is not recommended in pregnant or breastfeeding women due to a lack of available scientific evidence. Based on expert opinion, fennel preparations, other than fennel seed infusions and fennel honey, are contraindicated during pregnancy.

Interactions

Interactions with Drugs

  • Giant fennel (Ferula communis) may increase the risk of bleeding when taken with drugs that increase the risk of bleeding. Some examples include aspirin, anticoagulants ("blood thinners") such as warfarin (Coumadin®) or heparin, anti-platelet drugs such as clopidogrel (Plavix®), and non-steroidal anti-inflammatory drugs (NSAIDS) such as ibuprofen (Motrin®, Advil®) or naproxen (Naprosyn®, Aleve®).
  • Concurrent use of fennel and ciprofloxacin (Cipro®) may lead to decreased bioavailability of ciprofloxacin. Theoretically, fennel may also interfere similarly with other fluoroquinolone antibiotics.

Interactions with Herbs and Dietary Supplements

  • Fennel may increase the risk of bleeding when taken with herbs and supplements that are believed to increase the risk of bleeding. Multiple cases of bleeding have been reported with the use of Ginkgo biloba, and fewer cases with garlic and saw palmetto. Numerous other agents may theoretically increase the risk of bleeding, although this has not been proven in most cases.

Attribution
  • This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

Bibliography
  1. 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(4):58-61.
  2. Asero R. Fennel, cucumber, and melon allergy successfully treated with pollen-specific injection immunotherapy. Ann Allergy Asthma Immunol 2000;84(4):460-462.
  3. Berdonces JL. [Attention deficit and infantile hyperactivity]. Rev Enferm 2001;24(1):11-14.
  4. Chainy GB, Manna SK, Chaturvedi MM, et al. Anethole blocks both early and late cellular responses transduced by tumor necrosis factor: effect on NF-kappaB, AP-1, JNK, MAPKK and apoptosis. Oncogene 2000;19(25):2943-2950.
  5. De Vincenzi M, Silano M, Maialetti F, et al. Constituents of aromatic plants: II. Estragole. Fitoterapia 2000;71(6):725-729.
  6. Haze S, Sakai K, Gozu Y. Effects of fragrance inhalation on sympathetic activity in normal adults. Jpn J Pharmacol 2002;90(3):247-253.
  7. Iten F, Saller R. [Fennel tea: risk assessment of the phytogenic monosubstance estragole in comparison to the natural multicomponent mixture]. Forsch Komplementarmed Klass Naturheilkd 2004;11(2):104-108.
  8. Iyer LV, Ho MN, Shinn WM, et al. Glucuronidation of 1'-hydroxyestragole (1'-HE) by human UDP-glucuronosyltransferases UGT2B7 and UGT1A9. Toxicol Sci 2003;73(1):36-43.
  9. Muhlbauer RC, Lozano A, Reinli A, et al. Various selected vegetables, fruits, mushrooms and red wine residue inhibit bone resorption in rats. J Nutr 2003;133(11):3592-3597.
  10. Namavar JB, Tartifizadeh A, Khabnadideh S. Comparison of fennel and mefenamic acid for the treatment of primary dysmenorrhea. Int J Gynaecol Obstet 2003;80(2):153-157.
  11. Ng SS, Figg WD. Antitumor activity of herbal supplements in human prostate cancer xenografts implanted in immunodeficient mice. Anticancer Res 2003;23(5A):3585-3590.
  12. Saleh M, Hashem F, Grace M. Volatile oil of Egyptian sween fennel (Foeniculum vulgare, var. dulce. Alef.) and its effects on isolated smooth muscles. Pharm Pharmacol Lett 2005;6(1):5-7.
  13. Satyanarayana S, Sushruta K, Sarma GS, et al. Antioxidant activity of the aqueous extracts of spicy food additives--evaluation and comparison with ascorbic acid in in-vitro systems. J Herb Pharmacother 2004;4(2):1-10.
  14. Vasudevan K, Vembar S, Veeraraghavan K, et al. Influence of intragastric perfusion of aqueous spice extracts on acid secretion in anesthetized albino rats. Indian J Gastroenterol 2000;19(2):53-56.
  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(12):1391-1396.

Copyright © 2011 Natural Standard (www.naturalstandard.com)


The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.

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