Quercetin is a non-citrus bioflavonoid that possess beneficial antioxidant qualities. For added support, Solgar includes Vitamin C. As an antioxidant, Vitamin C also helps neutralize harmful free radicals in cells.Solgar"s Quercetin Complex includes the important flavonoid quercetin in a synergistic formula with Ester-C Plus and Bromelain. Ester-C Plus is exclusively formulated by Solgar and provides a patented method of supplementing pH neutral (non-acidic) vitamin C to prevent stomach irritation. In addition, Ester-C provides the naturally occurinring vitamin C metabolite - threonate. A special manufacturing process is employed to form a unique calcium ascorbate metabolite complex. Solgar"s Ester-C Plus offers the additional benefits of acerola, citrus bioflavonoids, rutin and rose hips in the Ester-C ascorbate metabolite complex.As a dietary supplement for adults, take two (2) vegetable capsules daily, preferably at mealtime, or as directed by a healthcare practitioner. Supplement Facts Serving Size: 2 vegetable capsules Amount Per Serving %DV Calories 5 Total Carbohydrate 1 g <1%* Vitamin C (as Ester-C, calcium ascorbate) 500 mg 833% Calcium (as Ester-C, calcium ascorbate) 50 mg 5% Quercetin 500 mg ** Bromelain (2000 GDU/g) 50 mg ** Citrus Bioflavonoid Complex 50 mg ** Rose Hips (fruit) 50 mg ** Acerola (berry) 50 mg ** Rutin 10 mg ** *Daily Values are based on a 2,000 calorie diet. **Daily Value (DV) not established. Other ingredients: Vegetable Cellulose, Vegetable Stearic Acid, Microcrystalline Cellulose, Silica, Magnesium Stearate. Uniquely incorporated into Ester-C PLus Complex.If you are pregnant, nursing, taking any medication or have a medical condition, please consult your healthcare practitioner before taking any dietary supplement.Keep out of reach of children.