Quercetin is the flavone aglycone (non-sugar-bound) form of the polyphenolic flavonoid rutin. It is the major bioflavonoid in the human diet. A potent phenolic antioxidant, research also supports Quercetin’s ability to stabilize the membranes of neutrophils (a kind of immune cell) and thereby balance the production of histamine and inflammatory signaling molecules.

Quercetin counters allergic reactions by inhibiting enzymes responsible for the production of inflammatory mediators. Also, Quercetin inhibits histamine release by stabilizing basophils and mast cells. Quercetin is widely used by those who suffer from constant allergies (such as dust) and seasonal allergies (such as hay fever).