Breathe a sigh of relief! HistaBlock supports the body in times of respiratory stress. A powerful combination of stinging nettle, quercetin, bromelain and immature orange peel (which contains synephrine), HistaBlock provides nutritional support for the respiratory system. This formula provides antioxidants and supports the body"s efforts to maintain mucous membrane health and nasal passage tissues. Mast cells are responsible for the drastic reactions that occur during seasonal respiratory attacks. HistaBlock"s unique formula helps stabilize these cells and inhibits swelling that occurs in the mucous membranes. Take 2 capsules with a meal twice daily.