What effect does fennel have?
The ripe fruits of fennel contain active ingredients that can help internally with digestive complaints (dyspeptic complaints) such as mild gastrointestinal cramps, flatulence and a feeling of fullness. Fennel can also be beneficial for mild menstrual cramps. The medicinal plant can also be used internally and externally for respiratory catarrh such as coughs caused by colds.
Effective ingredients
Fennel fruits contain a medicinal essential oil (Foeniculi aetheroleum). Among other things, it contains the sweet-tasting trans-anethole and the bitter-tasting fenchone. The oil of bitter fennel contains more fenchone and less anethole than that of sweet fennel (read more about these two varieties of fennel below). Other ingredients of fennel fruits include fatty oil and flavonoids.
Due to the sum of its ingredients, fennel can relieve gastrointestinal cramps and promote the movement (peristalsis) of the gastrointestinal tract. Anethole and fenchone have also been shown to have an expectorant effect. For these reasons, the use of fennel is recognized for dyspeptic complaints and inflammation of the respiratory tract.
Folk medicine use
How is fennel used?
The dried ripe fruits are used medicinally, mainly bitter fennel, but also sweet fennel and the essential oil isolated from the fruits. The oil has a stronger effect than the fruit.
Fennel as a household remedy
To prepare fennel tea, you should first freshly crush a teaspoon of fennel fruit (approx. 2.5 grams) or crush it in a mortar. This allows the essential oil to pass into the tea. Now pour 150 milliliters of boiling water over the chopped or crushed fruits, cover and leave to infuse for 10 to 15 minutes, then strain. You can drink a cup of warm fennel tea several times a day. You should not exceed the recommended daily dose of five to seven grams of fennel fruits.
The same daily dose also applies to children aged ten and over and adolescents. The following daily doses are recommended for younger age groups:
- one to three years: 1.5 – 3 grams
- four to nine years: 3 – 5 grams
For babies (0 to 12 months of age), you can use a little fennel tea to dilute milk or porridge. In principle, however, medicinal plant teas should only be used for babies after consulting a doctor or pharmacist.
Fennel honey is a popular home remedy for phlegm coughs: Stir 10 grams of freshly crushed fennel fruits into 100 grams of bee honey. Leave the mixture to stand for ten days before straining the fennel fruits. If you have a phlegm cough, you can stir one to two teaspoons of this fennel honey into a cup of hot water several times a day and drink it slowly.
Home remedies based on medicinal plants have their limits. If your symptoms persist over a longer period of time and do not improve or even get worse despite treatment, you should always consult a doctor.
Fennel in aromatherapy
Unless otherwise stated, the following formulations apply to healthy adults. For children, pregnant women, nursing mothers, the elderly and people with certain underlying conditions (such as asthma, epilepsy), the dosage often needs to be reduced or some essential oils avoided altogether. You should therefore first discuss the use of essential oils in such patient groups with an aromatherapist (e.g. a doctor or alternative practitioner with appropriate additional training).
Take 50 milliliters of sweet almond oil or sesame oil and mix in two drops of each of the following essential oils: fennel (sweet), anise, tarragon, coriander and petit grain bitter orange. Adults can use this oil blend for a relaxing clockwise abdominal massage if required.
Ready-made preparations with fennel
Fennel fruits can be bought loose, packaged in tea bags and in the form of ready-made tea blends (e.g. as a gastrointestinal tea). There are also other ready-made preparations available that are made on the basis of the fruit or the essential oil isolated from it. These include fennel honey, tincture, syrup and coated tablets. The honey and syrup are particularly suitable for children with colds: The sweet taste masks the bitter parts of the fennel oil.
For the exact use and dosage of fennel preparations and fennel oil, please read the relevant package leaflet and ask your doctor or pharmacist.
What side effects can fennel cause?
No side effects are known for fennel tea. Externally applied fennel oil occasionally triggers allergic reactions of the skin and respiratory tract.
What you should bear in mind when using fennel
If you are allergic to umbelliferous plants (such as celery, camomile, dill, caraway, aniseed) or to anethole, you must not use fennel.
Children and (dry) alcoholics should never be given alcoholic fennel preparations.
The following applies to fennel oil and all other essential oils: only use 100% natural essential oils – preferably those obtained from organically grown or wild-collected plants.
Before using fennel oil (and other essential oils), you should always test its compatibility using the arm flexion test: Put a drop of the essential oil in the crook of your arm and rub it in gently. If the affected area of skin turns red in the following hours, starts to itch and perhaps even forms pustules, you cannot tolerate the oil. You should then not use it!
Always store the essential oil away from light – when exposed to light, substances are formed in the oil that are harmful to health.
High doses of fennel oil can impair the effect of the contraceptive pill.
How to obtain fennel and its products
You can obtain fennel in various forms from your pharmacy or drugstore: You can purchase tea preparations, tinctures, honey and syrup, coated tablets, pastilles, juices with fennel or the essential oil there. Before use, please read the package leaflet carefully or speak to your doctor or pharmacist.
Interesting facts about fennel
The latter is a biennial cultivated form that is cultivated in temperate climate zones and also grows wild. Different varieties have developed from it over time: The bitter fennel (F. vulgare ssp. vulgare var. vulgare) and the sweet or Roman fennel (F. vulgare ssp. vulgare var. dulce) are both used medicinally. The vegetable or onion fennel (F. vulgare ssp. vulgare var. azoricum) is valued as a foodstuff.
Bitter and sweet fennel are plants up to two meters tall with upright, hard stems and narrow, feathery leaves. They bear small, yellow flowers in double umbels in summer, from which the fruits later develop: These are greenish-brown in color, up to about 1.2 centimeters long and have five light, angular protruding ribs. All parts of the plant have an aromatic scent, especially when rubbed between the fingers.
Wild fennel can also be used, but there is a high risk of confusion with other poisonous umbellifers. It is therefore important to carefully identify the plant when collecting it.
Fennel is also very popular in the spirits and food industry as a flavoring agent. It can be found in ouzo, absinthe, sambuco and spice mixtures, for example.
