Using Fennel to Treat Infant Colic

Various plants have been used to relieve of infantile colic, including catmint (Nepeta cataria), chamomille (Matricaria chamomilla), dill (Anethum graveolens), fennel (Foeniculum vulgare), lemon balm (Melissa officinalis), and others. Among these plants, fennel is the most frequently recommended by herbologists and naturopaths. All of these listed plants are rich in volatile oils, and their beneficial effects are attributed to volatile oils. The highest concentration of the fennel oil, ranging from 2 to 7%, is found in the seeds. Fennel volatile oil is a mixture of at least a dozen of different chemicals. The main ingredients of fennel seed oil are: anethole, 40 to 70%; fenchone, 10 to 30%; and estragole, 2 to 9%. Other components are present in concentrations usually less than 1%. Animal experiments have shown that fennel oil regulates contractility of the small intestine (36, 37, 38). Anethole has a chemical structure similar to a chemical that is naturally present in the body, called dopamine. Dopamine is known to have a relaxing effect on the intestine, and perhaps, explains why fennel has a beneficial effect on infantile colic.

Fennel has a long documented history of use, dating to an ancient Egypt. Even today, many lactating mothers in Asian countries routinely take fennel.

Preparations of fennel seed available on the market today exist as either teas or extracts, and contain variable and unpredictable concentrations of the volatile oil. This variability in oil concentration results from many factors, including soil and climate of the growing region, harvesting methods, manufacturing, and storage conditions. The inconsistency in the concentration of oil makes it difficult to obtain an effective, predictable and reproducible response. That explains why until recently there has only been one clinical study supporting the use of herbs, including fennel for infantile colic.

Fennel is a safe way to treat baby colic

Fennel has the remarkable qualities of being both effective and very safe. No acute or chronic toxic reactions to fennel, or to fennel products in humans have ever been reported. Laboratory animals given 3000 milligrams of fennel extract per kilogram of weight showed no sign of toxicity). Likewise, fennel seed oil tested in animal experiments has been found to be non-toxic at doses significantly higher, than those used in humans. For example, animals fed a diet containing 1% of anethole, the main component of fennel seed oil, had no toxic effects (40). The recommended daily amount of fennel seed oil for an average colicky 1 month old, who weighs approximately 4 kilograms (9 lbs.), would be 20 to 40 milligrams. Such an infant consumes approximately 600 gram (20 oz) of formula, or milk per day. Therefore, 20 to 40 mg. of fennel seed oil given to an infant daily would be equal to 0.0035 to 0.007% of the total daily food consumption, which is 140 to 280 times less, than in a study quoted.

Besides its antispasmodic qualities, fennel seed oil has antioxidant and antimicrobial activity, probably attributed to anethole, which itself has been shown to have anti-inflammatory, antibacterial and also anticarcinogenic effects (41, 42, 43).

Even though fennel is mentioned as an allergen, the allerginicity of fennel is extremely low, probably much lower than of milk, soy or eggs. In fact, since 1948 there were only two reports of allergic reaction to fennel plant in the English literature. However, all statements of experts regarding the allerginicity of fennel are based on these two reports. It has been shown that fennel allergy is caused by pollen (46), which is always present in unprocessed seeds. Fennel seed oil, which is produced by distillation of fennel seeds, has no pollen particles in it, and therefore, cannot produce allergic reactions.

Undiluted, or 100% fennel seed oil applied to the skin for a long period of time can produce local irritation. However, diluted fennel seed oil is not irritating. In an experiment on human volunteers, application of 4% oil did not produce any reactions.

The Council of Europe included fennel in the list of spices and seasonings in 1973. Fennel seed oil has been on the FDA's GRAS (Generally Recommended As Safe) list of flavoring substances in the United States since the 1970's.

View our bibliography of infant colic research sources.