Aller-Response™ is a seasonal formula featuring quercetin. Human cell culture studies with quercetin demonstrated its capability to inhibit the release of histamines. Ginkgolide B, in human cell culture studies, was found to be a potent inhibitor of platelet-activating factor, a substance that stimulates the release of histamine from immune cells. Vitamin A and vitamin C, along with the mineral zinc, Enhance support the Defense mechanism of body.