Alfalfa has been used for thousands of years in many parts of the world as a source of food for people and livestock and as a medicinal herb. It is probably more useful as a source of easily accessible nutrients than as a medicinal herb.

Alfalfa is an excellent source of most vitamins, including vitamins A, D, E, and K. Vitamin K is critical in blood clotting, so alfalfa may have some use in improving clotting. It also contains trace minerals such as calcium, magnesium, iron, phosphorous, and potassium.

Alfalfa is also higher in protein than many other plant foods. This abundance of nutrients has made alfalfa a popular tonic for convalescents when brewed into tea. In addition to using the seeds and leaves as food, alfalfa has a long history of folk use in Europe as a diuretic or ‘‘water pill.’’

It is also said that alfalfa can lower cholesterol. Alfalfa is used as to treat arthritis, diabetes, digestive problems, weight loss, ulcers, kidney and bladder problems, prostate conditions, asthma, and hay fever. Alfalfa is also said to be estrogenic (estrogen-like).

Alfalfa is not native to the United States and did not arrive until around 1850. However, once introduced, it spread rapidly and was adapted by Native Americans as a food source for both humans and animals. The seeds were often ground and used as a flour to make mush. The leaves were eaten as vegetable.

The main medical use for alfalfa in the United States was as a nutritious tea or tonic. In China, alfalfa and a closely related species tooth-bur clover, Medicago hispida or nan mu xu have been used since the sixth century. Alfalfa is a minor herb in traditional Chinese medicine.

It is considered to be bitter in taste and have a neutral nature. Traditional Chinese healers use alfalfa leaves to cleanse the digestive system and to rid the bladder of stones. The root of alfalfa is used in Chinese medicine to reduce fever, improve urine flow, and treat jaundice, kidney stones, and night blindness.

Contrary to the Western belief that alfalfa will aid in weight gain, Chinese herbalists believe that extended use of alfalfa will cause weight loss. Alfalfa contains hundreds of biologically active compounds, making it difficult to analyze and to ascribe healing properties to any particular component.

In addition to the nutrients mentioned alfalfa contains two to three percent saponin glycosides. In test tube and animal studies, saponin glycosides have been shown to lower cholesterol, but there is no evidence that this cholesterol-lowering effect occurs in humans.

In addition, saponin glycosides are known to cause red blood cells to break open (hemolysis) and to interfere with the body’s utilization of vitamin E. No modern scientific evidence exists that alfalfa increases urine output, effectively treats diabetes, aids kidney or bladder disorders, improves arthritis, reduces ulcers, or treats respiratory problems.

Similarly, there is no scientific evidence that alfalfa either stimulates the appetite or promotes weight loss. There is no evidence that alfalfa has any estrogenic effect on menstruation. There is evidence, however, that although for most people alfalfa is harmless, for some people it can be dangerous to use.