![HistDAO](http://shop.greenbergregen.com/cdn/shop/products/HistDAO_{width}x.png?v=1610662940)
HistDAO™ is a patented enzyme formula containing diamine oxidase (DAO)—the main enzyme responsible for the degradation of ingested histamine. This enzyme has been clinically tested and found to break down food-derived histamine in the digestive tract. DAO is not absorbed and does not have systemic activity. HistDAO does not manage or address antibody-related or IgE-related food allergies.*