Use of the dried leaves of alfalfa in recommended amounts 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.²⁶ It has also been linked to the reactivation of SLE in people consuming alfalfa tablets.²⁷ 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.