a hereditary disorder involving an allergic-like reaction to the broad, or fava, bean (Vicia faba). Susceptible persons may develop a blood disorder (hemolytic anemia) by eating the beans, or even by walking through a field where the plants are in flower.

The known distribution of the disease is largely limited to people of Mediterranean origins (Spaniards, Italians, Greeks, Armenians, and Jews). Susceptibility to favism is inherited as a sex-linked trait and appears to be closely related to glucose-6-phosphate dehydrogenase deficiency (q.v.).