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Fennel

What are other names for this remedy?

Type of medicine: natural remedy

Scientific and common names: Foeniculum vulgare, Foeniculum officinale, fenchel, bitter fennel, carosella, common fennel, finnochio, garden fennel, sweet fennel, wild fennel

What is fennel?

The fennel plant can grow to about 4 feet tall. The leaves are very feathery and are green with a hint of blue. The fruits are large and have a spicy licorice taste. All parts of the plant are usable. The leaves are used in salads and in fish dishes. Fennel seeds are used in soups, sauces, and baked goods. The dried, ripe seeds are used to make medicine.

What is it used for?

Fennel has been used to treat:

  • airway inflammation
  • breast-feeding problems (lack of milk production)
  • bronchitis, coughs, and sore throats
  • abnormal lack of menstrual periods
  • loss of appetite
  • stomach upset, indigestion, colic, and stomach cramps
  • vision problems.

The US Food and Drug Administration (FDA) does not approve uses for natural remedies. The FDA does not inspect or regulate natural remedies the way they do prescription medicines.

How is it taken?

Fennel can be taken as a tea, tincture, or raw seeds. Do not use fennel oil.

What should I watch out for?

Do not take fennel supplements if you are allergic to carrots, celery, or mugwort. Fennel has effects similar to estrogen. Do not use this remedy if you have a hormone-sensitive condition such as:

  • breast, uterine, or ovarian cancer
  • endometriosis or uterine fibroids.

Fennel seems to be safe for short-term use, but do not use fennel for a long time or in large amounts.

Fennel may make your skin more sensitive to the sun, which may lead to painful sunburns. While you are taking this remedy, avoid long exposure to the sun. Wear protective clothing, a hat, and sunscreen lotion when you need to be outdoors. Do not use a sunlamp. If you get a severe sunburn, contact your healthcare provider right away.

Females of childbearing age: Do not take this remedy if you are pregnant or breast-feeding.

Talk to your healthcare provider or pharmacist about any natural remedy that you are using or considering. If your provider does not give you specific instructions, follow the directions that come with the package. Do not take more or take it longer than recommended. Ask about anything you do not understand. Remember:

  • Natural remedies are not always safe.
  • You should not take them if you are pregnant or breast-feeding without your healthcare provider's approval. They should not be taken by infants, children, or older adults without your provider's approval.
  • They affect your body and may interact with prescription medicines that you take.
  • Natural remedies are not standardized and may have different strengths and effects. They may be contaminated.

What are the possible side effects?

Along with its desirable effects, this remedy may cause some unwanted side effects. Some side effects may be very serious. Some side effects may go away as your body adjusts to the remedy. Tell your healthcare provider if you have any side effects that continue or get worse.

Life-threatening (Report these to your healthcare provider right away. If you cannot reach your healthcare provider right away, get emergency medical care or call 911 for help): Allergic reaction (hives; itching; rash; trouble breathing; tightness in your chest; swelling of your lips, tongue, and throat), seizures.

Other: Vomiting, nausea, sun sensitivity.

What products might interact with this remedy?

When you take this remedy with other medicines, it can change the way this remedy or any of the medicines work. Vitamins and certain foods may also interact. Using these products together might cause harmful side effects. Before taking this remedy, talk to your healthcare provider if you are taking:

  • birth control pills and hormone therapy such as estrogen (Premarin, Prempro, Cenestin) or estradiol (Alora, Estrace)
  • tamoxifen (Nolvadex).

Keep a list of all your medicines (prescription, nonprescription, supplements, natural remedies, and vitamins) with you. Be sure that you tell all healthcare providers who treat you about all the products you are taking.


Keep all natural remedies and medicines out of the reach of children.

This advisory includes select information only. The information was obtained from scientific journals, study reports, and other documents. The author and publisher make no warranty, expressed or implied, as to the information. The advisory may not include all side effects associated with a remedy or interactions with other medicines. Nothing herein shall constitute a recommendation for the use of any remedy. Ask your healthcare provider or pharmacist for more information.

Developed by McKesson Corporation
Published by McKesson Corporation.
Last modified: 2007-01-18
Last reviewed: 2007-01-18
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
Copyright © 2007 McKesson Corporation and/or one of its subsidiaries. All Rights Reserved.
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