Food allergens are components of foodstuff and additives that when digested, in contact or inhale cause an immune reaction known as food allergy.

Although some allergies occur more frequently than others, and there are about 160 foods that can cause allergic reactions, the most common ones are those to the cow milk, eggs, legumes (including soy), wheat/gluten, fish, shellfish, fruits, and nuts, such as peanuts and walnuts.