Allergies are conditions in which the body's immune system becomes sensitive and reacts to substances called allergens. Some common allergens include pollen, dust, animal dander, most chemicals, food and medications. Vitamin C may help prevent allergy symptoms and may help reduce inflammation associated with allergic symptoms. In addition, bioflavinoids, which are plant substances closely related to Vitamin C, may also produce similar effects. Finally, Vitamins A and E may help with the normal functioning of the immune system and provide antioxidant protection.