Common name: Lucerne.  Botanical name: Medicago sativa.  Alfalfa is a member of the pea family and is native to western Asia and the eastern Mediterranean region. Alfalfa sprouts have become a popular food. Alfalfa herbal supplements primarily use the dried leaves of the plant. The heat-treated seeds of the plant have also been used.

Alfalfa has been used in connection with the high cholesterol, menopause and poor appetite.

Many years ago, traditional Chinese physicians used young alfalfa leaves to treat disorders of the digestive tract.  Similarly, the Ayurvedic physicians of India prescribed the leaves and flowering tops for poor digestion. Alfalfa was also considered therapeutic for water retention and arthritis. North American Indians recommended alfalfa to treat jaundice and to encourage blood clotting.

Although conspicuously absent from many classic textbooks on herbal medicine, alfalfa did find a home in the texts of the Eclectic physicians (19th-century physicians in the United States who used herbal therapies) as a tonic for indigestion, dyspepsia, anemia, loss of appetite, and poor assimilation of nutrients.  These physicians also recommended the alfalfa plant to stimulate lactation in nursing mothers, and the seeds were made into a poultice for the treatment of boils and insect bites.

Active constituents:  While the medicinal benefits of alfalfa are poorly understood, the constituents in alfalfa have been extensively studied. The leaves contain approximately 2–3% saponins.  Animal studies suggest that these constituents block absorption of cholesterol and prevent the formation of atherosclerotic plaques.  One small human trial found that 120 grams per day of heat-treated alfalfa seeds for eight weeks led to a modest reduction in cholesterol. However, consuming the large amounts of alfalfa seeds (80–120 grams per day) needed to supply high amounts of these saponins may potentially cause damage to red blood cells in the body.  Herbalists also claim that alfalfa may be helpful for people with diabetes. But while high amounts of a water extract of the leaves led to increased insulin release in animal studies, there is no evidence that alfalfa would be useful for the treatment of diabetes in humans.

Alfalfa leaves also contain flavones, isoflavones, sterols, and coumarin derivatives. The isoflavones are thought to be responsible for the estrogen-like effects seen in animal studies. Although this has not been confirmed with human trials, alfalfa is sometimes used to treat menopause symptoms.

Alfalfa contains protein and vitamin A, vitamin B1, vitamin B6, vitamin C, vitamin E, and vitamin K. Nutrient analysis demonstrates the presence of calcium, potassium, iron, and zinc.

Dried alfalfa leaf is available as a bulk herb, and in tablets or capsules. It is also available in liquid extracts. No therapeutic amount of alfalfa has been established for humans. Some herbalists recommend 500–1,000 mg of the dried leaf per day or 1–2 ml of tincture three times per day.

Use of the dried leaves of alfalfa in the amounts listed above is usually safe. There have been isolated reports of people who are allergic to alfalfa. Ingestion of very large amounts (the equivalent of several servings) of the seed and/or sprouts has been linked to the onset of systemic lupus erythematosus (SLE) in animal studies.  It has also been linked to the reactivation of SLE in people consuming alfalfa tablets.  SLE is an autoimmune illness characterized by inflamed joints and a high risk of damage to kidneys and other organs. The chemical responsible for this effect is believed to be canavanine. At the time of writing, there were no well-known drug interactions with alfalfa.