R-Hist Px formula is rich in Rosmarinic Acid and quercetin, both of which have potent antioxidant activity capable of supporting normal immune response. This formula maintains healthy nasal and gastric mucous membrane function and can help maintain neutrophil and eosinophil activity. Quercetin is a bioflavonoid and is optimally absorbed in its natural form. It helps to support the body’s normal inflammatory response via balancing mast cell histamine release . Rosmarinic Acid is well studied for supporting healthy probiotic bacteria levels in the gastrointestinal tract.