From the Manufacturer's Label:
Quercetin is a powerful antioxidant that helps support your immune system. It provides a powerful antioxidant boost to help protect against harmful free radicals.
•Helps Support Immune System
•With Vitamin C and Bioflavonoids
Manufactured by NatrolFree Of: Yeast, wheat, corn, milk, egg, soy, glutens, artificial colors, added sugar, starch and preservatives.