Food hypersensitivity, also known as food allergy, is a common immune system disorder that occurs when the body reacts abnormally to certain foods. The symptoms of food hypersensitivity can range from mild to severe and can include hives, swelling of the lips, tongue or throat, abdominal pain, diarrhea, and vomiting. Other synonyms for food hypersensitivity include food intolerance, food sensitivity, allergic reaction to food, and food allergy syndrome. The underlying cause of food hypersensitivity is often unknown, but it is thought to be related to both genetic and environmental factors. Treatment for food hypersensitivity may include avoiding triggering foods and taking antihistamines or epinephrine in severe cases.