Soy allergy is an allergic reaction to soybeans and foods that contain ingredients derived from this legume. Products that contain soy – including some inks, soaps and cosmetics – can also cause reactions.

Soy allergy is most commonly found in infants and only rarely in adults. Symptoms include a wide range of reactions, from nasal congestion to bronchospasm (sudden tightening of the airways) and anaphylaxis (a dangerous allergic reaction involving two or more body systems).

Soybeans are high in protein, making soy products popular for vegetarians and other people seeking meat alternatives. Avoidance of soy-based foods and ingredients is the only certain way to prevent symptoms related to soy allergy.