Fennel is a herb with the botanical name foeniculum vulgare. It's also known as bitter fennel, sweet fennel, wild fennel, carosella, Florence fennel, finocchio, garden fennel and large fennel..

Fennel originally grew along the seashores of the Mediterranean coast and grows wild in many countries of temperate Europe. Fennel is cultivated in the south of France, India and Russia and grows throughout the year to two metres or more in height.

The plant develops bright golden flowers and leathery leaves. The stem is bright green and smooth to the touch. The fruit is about 1cm long and 0.25 cm wide, oblong, cylindrical and slightly curved with a sweet taste and a characteristic odour. The parts used are the seeds (which contain several active constituents including up to 8 per cent of an essential oil consisting mainly of anethole), a bitter principle (fenchone), flavonoids, coumarins, sterols, fixed oils and sugars.

Health benefits • Fennel is mainly used for its calming effect on the digestive system. The oil regulates peristaltic functions of the intestines, reducing spasms, reducing emptying time and increasing the passage of gas. It can be used for griping, colic, flatulence or wind and other disturbances of bowel and intestinal function, particularly where there is inadequate digestive tone. • Fennel has been used by breastfeeding mothers to increase milk supply. For breastfeeding mothers, infuse fennel seeds to make a tea. • Fennel has an antibiotic and anti-inflammatory action and can be used for acute and chronic infections. An expectorant action makes it useful for any respiratory infections where there is mucus congestion in the lungs and sinuses. • Fennel can be used locally in an eye wash or gargle.

How to use • Always consult your healthcare professional to advise you on dosages and any possible medical interactions. • Fennel tea is made by pouring boiling water on a teaspoonful of bruised fennel seeds. Fennel tea is reputed to help digestion and to prevent flatulence.

Cautions • Herbal supplements can alter the effects of certain drugs, including prescription medications. Always tell your doctor about any prescription medications, non-prescription medications, herbs or other dietary supplements you are taking. • Fennel isn't recommended for pregnant women. • Use fennel with caution if you're allergic to celery, carrots or mugwort. • Fennel reduces the effectiveness of the antibiotic drug ciprofloxacin, so the two substances shouldn't be taken together. • Fennel contains oestrogen-like substances that may interact with hormone therapy, including fertility treatments and the oral contraceptive pill • Possible side-effects of fennel include stomach upset and photodermatitis (skin irritation from sunlight). • Fennel contains substances that, if ingested, can cause seizures so this herb should be used with extreme caution by people with epilepsy.