Seeds of the fennel, Foeniculum vulgare, plant have traditionally been used as food and medicine in the Chinese, Indian, Egyptian and Greek civilizations for centuries. The seeds are commonly used to treat several different gastrointestinal issues, but are most widely known as a remedy for gas in infants. Modern studies focusing solely on fennel seed for treating humans are limited, but constituents found in the seeds are known to be beneficial to the digestive system. Fennel seed is considered safe to take, but you should consult a qualified health practitioner before taking them for digestive health.
The fennel plant is a perennial herb -- meaning it grows for more than two years -- native to southern Europe and the Mediterranean area. The yellow flowers of the plant produce a fruit, which when dried is commonly referred to as a fennel seed. The seeds relax smooth muscles, stimulate the flow of bile and reduce pain, according to the NYU Langone Medical Center, which may account for its potential benefits for digestive health.
Fennel is used as medicinal treatment for several types of health issues, such as menstruation, but its seeds are the component typically used to treat digestive ailments. The seeds are widely known as a carminative, which means they help prevent or remove gas from the intestines. They are a common ingredient in a traditional decoction called "gripe water," which is used to treat colic in infants -- a condition that commonly includes gas as a symptom. Fennel seeds also are traditionally used to treat several maladies that cause abdominal pain. Traditional Chinese medicine herbal formulas, for example, contain fennel seeds to help treat gastroenteritis, hernias and indigestion.
Although studies on humans are limited, one double-blind, placebo-based study published in a 2003 edition of "Alternative Therapies in Health and Medicine" reported that infants given fennel seed oil experienced significant reduction in colic symptoms when compared to placebo. Drugs.com reports that, based on a small preliminary study, fennel seeds -- when combined with other herbs -- were found to help chronic constipation. According to the University of Michigan Health System, studies in test tubes or on animals have shown that fennel seeds may also help destroy bacteria and fungi in the intestinal tract, as well as help indigestion, heartburn and low stomach acidity. More tests are needed, however, to determine efficacy in humans.
The recommended dosage of fennel seeds for most adults is 1 teaspoon to 1 1/2 teaspoons of seeds, according to the NYU Langone Medical Center. The University of Maryland Medical Center recommends drinking it in tea form for colic and states breastfeeding women can drink the tea without problem, although you should consult a pediatrician before giving it to infants. Fennel seed is considered safe when taken as a food, but it may interfere with the absorption of certain medications, particularly antibiotics. If you are on medication, pregnant or being treated for any other health issue, consult a doctor before taking fennel seed.