Health Library Explorer


Botanical name(s):

Medicago sativa. Family: Fabaceae

Other name(s):

hay, lucerne, purple medic

General description

Alfalfa is a perennial plant 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.

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

Unsubstantiated claims


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. Alfalfa seems to increase certain immune system functions.

In some cases, alfalfa sprouts have been contaminated with salmonella and E. coli. This has caused outbreaks of diarrhea 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 always store alfalfa sprouts in the refrigerator and use them soon after you buy them. In addition, be sure to rinse them with running water before eating.

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

Alfalfa may reduce how well birth control pills work. If you take alfalfa and use birth control pills that contain estrogen, use an additional form of birth control.

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

Alfalfa may decrease blood sugar. If you take alfalfa along with certain diabetes medications, your blood sugar might go too low. Be sure to check your blood sugar regularly if you have diabetes and take alfalfa.

Online Medical Reviewer: Brittany Poulson MDA RDN CD CDE
Online Medical Reviewer: Diane Horowitz MD
Online Medical Reviewer: Heather M Trevino BSN RNC
Date Last Reviewed: 2/1/2021
About StayWell | StayWell Disclaimer