Food allergens are substances in certain foods that can trigger an abnormal immune response in some individuals. Common food allergens include peanuts, tree nuts, milk, eggs, wheat, soy, fish, and shellfish. When a person with a food allergy consumes these foods, their body mistakenly identifies them as harmful, leading to symptoms that can range from mild to severe. Symptoms of food allergies can include hives, swelling, stomach pain, and in extreme cases, anaphylaxis, which is a life-threatening reaction. It is important for individuals with food allergies to read food labels carefully and avoid foods that contain their specific allergens to prevent adverse reactions.