Legumes include beans, peas and lentils. Peanut is botanically a bean. Peanuts are one of the most allergenic foods and the most frequent cause of very severe and occasionally fatal reactions.

Allergy to peanuts is often established in childhood and usually maintained throughout life.

Some peanut allergic persons are so sensitive that very tiny amounts of peanut can cause a reaction. Thus the carryover of materials on utensils used for serving foods can be enough in some individuals to cause a reaction.

The legumes have multiple allergens, which are present in the raw and cooked foods. The main allergens are the proteins used by the seed as a food store for it to grow into a seedling.