This information describes the common uses of Alfalfa, how it works, and its possible side effects.

Common Name

Buffalo Herb, Lucerne, Purple Medick, Purple Medicle, Purple Medic

How It Works

Alfalfa may be effective at reducing cholesterol levels, but there is no evidence that it can treat cancer and it has many side effects.

Alfalfa contains fiber and a substance called saponins, which are thought to bind with cholesterol in the body and may reduce cholesterol levels. Alfalfa plants also contain phytoestrogens, which act like some human hormones. In fact, alfalfa phytoestrogens caused the growth of estrogen-dependent breast cancer cells. Alfalfa seeds also contain a toxic amino acid, L-canavanine. Levels of this amino acid vary widely across various cultivations of plants, and decrease as the plant matures. It is thought that this amino acid may be responsible for alfalfa’s ability to cause a relapse of lupus symptoms in patients who are in remission from the disease, and large levels of L-canavanine from alfalfa supplementation may have additional detrimental effects in humans.

Because it also has a significant estrogenic effect, patients with hormone-sensitive cancers should avoid alfalfa.

Purported Uses

  • To treat diabetes
    Although alfalfa appears to lower blood glucose levels in animals, no studies have tested whether it has any significant effect in patients with diabetes.
  • To treat high cholesterol
    Two small trials have shown that alfalfa supplements lower cholesterol levels in people with high cholesterol, but larger, controlled trials are necessary to confirm these results.
  • As a diuretic
    This is not backed by experimental evidence.
  • To treat gastrointestinal disorders
    No scientific evidence supports this use.
  • To treat asthma and hay fever
    There are no studies to back this use.
  • To treat thyroid problems
    No scientific evidence supports this use.
  • To increase lactation
    Scientific evidence is lacking for this claim.
  • To promote menstruation
    There are no studies to support this claim.

Patient Warnings

  • Alfalfa sprouts have been linked to a number of food poisoning outbreaks in California and Europe.

Do Not Take If

  • You are pregnant or nursing (Because of its hormonal effects, alfalfa should be avoided during pregnancy and nursing.)
  • You have lupus (Patients with systematic lupus erythematosus should avoid alfalfa tablets because they may lead to relapse.)
  • You have gout (Due to the high content of purines, alfalfa should be avoided in patients with gout.)
  • You have hormone-sensitive cancer such as breast, prostate, cervical, or uterine cancers (Estrogenic effects have been found in alfalfa.)

Side Effects

  • Minor gastrointestinal distress (e.g. gas, diarrhea, abdominal discomfort).