Fennel and anise are very similar herb-like plants that are used for the volatile oils and other components in their seeds. Although the two herbs are sometimes mistaken for one another, fennel is the plant also called Foeniculum vulgare, while anise is the plant Pimpinella anisum. Anise and fennel seeds may offer some health benefits, but you should consult your doctor before taking either herb for any medicinal purpose. No widely-accepted scientific research supports the use of fennel or anise to treat any medical condition.
Benefits
Both anise and fennel seeds are sometimes recommended for helping to treat colic in infants, indigestion and gas. Fennel is also used for relieving menstrual pain, heartburn and symptoms related to irritable bowel syndrome (IBS). Anise is used to treat bronchitis and other respiratory conditions, kill parasites, relieve constipation and treat head lice, notes the University of Michigan Health System.
Functions
Anise seeds contain volatile oils that appear to offer antispasmodic, laxative and antiparasitic effects. Specifically, anise’s volatile oil contains terpenoids, especially anethole, which provide these actions and also have mild estrogenic effects. Fennel seeds also contain anethole, but fennel also contains other constituents with diuretic, antimicrobial, fever-reducing, pain-relieving and bile-stimulating actions. But little is known about these specific actions of fennel and anise in the human body.
Dosages
A typical dosage of fennel seeds may be 1 to 1½ tsp. each day in the form of a tea or in capsules, says the University of Pittsburgh Medical Center (UPMC). The typical dosage of anise is ½ teaspoon of seeds taken three times daily in a tea or capsule, says UPMC. Alternatively, you might take 1 to 2 tsp. of fennel seed tincture three times daily between meals. Ask your physician about the proper dosage of anise or fennel that’s right for you before taking these herbs.
Medical Evidence
A 2003 double-blind clinical trial published in Alternative Therapies in Health and Medicine found that fennel seed oil relieved colic symptoms in infants significantly better than a placebo, according to UPMC. Another double-blind study published in the Journal of Pediatrics in 1993 discovered that an herbal tea made from fennel seeds was effective in treating infantile colic. No other human trials have investigated fennel’s medicinal uses. Although anise has been used in traditional medicine to relieve gas and colic, no human studies have confirmed these or any other benefits.
Warnings
Because both anise and fennel seeds are common spices used throughout the world, they’re generally considered safe for consumption. Fennel might interfere with the absorption of certain antibiotics in the ciprofloxacin and fluoroquinolone drug families, warns UPMC. Also, you should avoid taking fennel and anise seeds if you have an estrogen-related illness such as breast cancer due to the herbs’ potential estrogenic effects. In rare cases, fennel and anise seeds can cause allergic reactions in some people.
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