Food allergy is a medical condition in which exposure to a particular food triggers a harmful immune response. This reaction occurs because the immune system attacks proteins in the food that are otherwise harmless. These proteins are known as allergens, and even a small amount can cause a significant allergic reaction.

Food allergies should not be confused with food intolerances, which are less severe and do not involve the immune system. Unlike food intolerances, food allergies can be life-threatening and require strict avoidance of the allergen.