IMPORTANT BIOFLAVINOID: Solgar Quercetin Complex includes the most important bioflavonoid, Quercetin, along with Ester-C Plus and Bromelain in a synergistic formula to provide immune health support. This complex also provides natural seasonal support as well as unique antioxidant protection WHAT IS QUERCETIN: Quercetin is found in food such as onions and possesses antioxidant properties which help to stabilize cell membranes. ESTER-C PLUS BENEFITS: Ester-C Plus provides a pH neutral, non-acidic, patented form of Vitamin C that is gentle on the stomach. In addition Ester-C Plus offers the benefits of incorporating acerola berry, citrus bioflavonoids, rose hips and rutin