Natural Factors Quercetin capsules are enhanced with Citrus Bioflavonoids Bromelain and Rutin. Quercetin a popular bioflavonoid is essential to optimize the bodyGÇÖs use of Vitamin C. Bioflavonoids are brightly-colored substances that are found in fruits and vegetables typically as companions to Vitamin C. Bioflavonoids are essential for proper absorption of Vitamin C and have been shown to have antioxidant properties increase capillary strength and keep collagen healthy.*Other products from HerbsPro