While it has long been known that the reduction of nitrite to nitric oxide (NO) forms iron-nitrosyl-myoglobin and is the basis of meat curing, a greater biological activity of the nitrite anion has only recently been appreciated. In the stomach, NO is formed from acidic reduction of nitrite and increases mucous barrier thickness and gastric blood flow (see the related study beginning on page 106). Nitrite levels in blood reflect NO production from endothelial NO synthase enzymes, and recent data suggest that nitrite contributes to blood flow regulation by reaction with deoxygenated hemoglobin and tissue heme proteins to form NO.