Spring is the time of year when many people start to notice seasonal allergy symptoms or hayfever. Studies have found that symptoms of seasonal allergies can be helped by eating plant foods which have a high content of  Quercetin . Quercetin  is a flavonoid  compound  which can act as an antihistamine in the body. It does this by stabilising  mast cells which release histamine and trigger allergy symptoms. Fruits and vegetables are the main source of  Quercetin in the diet especially kale, asparagus, apples and many types of berries.