Source Naturals Activated Quercetin Bioflavonoid Complex is a unique bioflavonoid complex that provides support for the cardiovascular system. Found in onions, green tea, apples and other plant sources, quercetin is an antioxidant flavonoid that delivers free radical protection for blood vessels and other vital tissues throughout the body. Contains no  yeast, dairy, egg, gluten, soy, wheat, sugar, preservatives, artificial color, flavor or fragrance.