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Botanical name(s):

Medicago sativa. Family: Fabaceae

Other name(s):

hay, lucerne, purple medic

General description

Alfalfa is a perennial grown worldwide. It’s used as a feedstock for cattle. It looks like a clover. But it can grow to a height of 2 to 3 feet. It blooms in the summer with purple or blue flowers. At harvest time, alfalfa is mowed, field dried, and baled. The baled hay can be fed directly to cattle. Or it can be ground to a coarse powder first. It can also be enriched with grain or other supplements.

Alfalfa seeds are sprouted and used as garnish for salads and other foods. Alfalfa leaves contain triterpenoid saponins (soyasapogenols). These can reduce cholesterol absorption and vascular plaque formation in animals, but they can also cause hemolytic anemia. The leaves are safer to use than the seeds. This is because alfalfa seeds contain the toxic amino acid L-canavanine (arginine analog).

Medically valid uses

Alfalfa has a long history as a medicinal herb. But there is no scientific evidence supporting its use.

However, studies show that L-canavanine, a non-protein amino acid in alfalfa (in the seeds and sprouts), can cause lupus or make existing lupus worse. Lupus is an autoimmune disease that affects connective tissue. This is found in every organ of your body.

Unsubstantiated claims

Please note that this section reports on claims that have not yet been substantiated through scientific studies.

There are claims that alfalfa may help allergies, thyroid problems, blood and liver toxicity, asthma, and how the pituitary works. It’s also said to reduce the risk of heart attacks. It may also help with an inflamed prostate, rheumatoid arthritis, stomach problems, and diabetes. There are reports that alfalfa works as a diuretic.

Dosing format

Follow packaging instructions for the correct dose.

Side effects, toxicity, and interactions

Alfalfa is considered safe when taken by healthy people. It can cause or make lupus worse in some cases. If you have lupus, you should not use alfalfa. Alfalfa seems to increase certain immune system functions. It may also make conditions linked with an overactive immune system worse. These can include rheumatoid arthritis or multiple sclerosis.

In some cases, alfalfa sprouts have been contaminated with Salmonella and E. coli. This has caused outbreaks of diarrheal disease and hemolytic uremic syndrome (HUS). This is a disease associated with E. coli. There have been improvements in how alfalfa is processed, which has lowered these risks. To reduce your risk, you should eat alfalfa sprouts right after you buy them. Don’t store them for a long time.

Women who are pregnant or breastfeeding should talk to their healthcare provider before taking any herbal medicines.

Alfalfa contains high amounts of vitamin K. This can reduce the blood thinning (anticoagulant) action of the medicine Warfarin. If you’re taking this drug, ask your healthcare provider how much alfalfa you can eat.


Online Medical Reviewer: Poulson, Brittany, RD
Online Medical Reviewer: Wilkins, Joanna, R.D., C.D.
Date Last Reviewed: 7/1/2016