Herbs of Gold Quercetin Complex provides 500mg of quercetin blended with bioflavonoids and vitamin C to support healthy immune system function. Quercetin Complex contains bioflavonoids, a group of plant pigments that give colour to many fruits and vegetables including, onions, apples, broccoli and berries. Quercetin, rutin and citrus bioflavonoids have antioxidant activity that decreases free radicals formed in the body and helps reduce damage to body cells. Quercetin Complex supports blood vessel and capillary health.