Sodium nitrite which contains no greater than 0.02% by weight of sodium carbonate and no greater than 10 ppm of anti-caking agent, wherein the sodium nitrite has a loss on drying of no greater than 0.25% by weight; wherein the water content in the sodium nitrite is no greater than 0.5% by weight; wherein the sodium nitrite contains no greater than 0.4% by weight of sodium nitrate, no greater than 0.005% by weight of insoluble matter, no greater than 0.005% by weight of chloride, no greater than 0.01% by weight of sulfate, no greater than 0.001% by weight of iron, no greater than 0.01% by weight of calcium, no greater than 0.005% by weight of potassium, no greater than 0.05 ppm of mercury, no greater than 2 ppm of aluminum, no greater than 3 ppm of arsenic, and no greater than 0.003% by weight of selenium; wherein the sodium nitrite contains no greater than 10 ppm, no greater than 100 ppm, no greater than 500 ppm, no greater than 1000 ppm, or no greater than 5000 ppm of organic volatile impurities; wherein the total non-volatile organic carbon content in the sodium nitrite is no greater than 2.5 ppm, or no greater than 10 ppm; wherein the sodium nitrite has total aerobic count of microbial load of no greater than 100 CFU/g, has total yeast and mold count of no greater than 20 CFU/g, contains no greater than 0.25 EU/mg of bacterial endotoxins; wherein the sodium nitrite contains no less than 97% by weight and no greater than 101% by weight of sodium nitrite as measured by USP colormetric assay; and wherein the heavy metal content in the sodium nitrite is no greater than 10 ppm, for use in a method of treating, preventing or reducing the risk of a disease or condition associated with the cardiovascular system, wherein the disease or condition associated with the cardiovascular system is angina, claudication, peripheral artery disease, critical limb ischemia, tissue ischemia-reperfusion injury, intravascular thrombosis, an ischemic central nervous system event or a cardiovascular disease; or for use in a method of increasing blood flow to tissue, wherein blood flow to said tissue is decreased directly or indirectly by cardiopulmonary bypass, coronary disease, cardiac ischemia syndrome, angina, angioplasty, myocardial ischemia or tissue ischemia. wherein the sodium nitrite has a loss on drying of no greater than 0.25% by weight; wherein the water content in the sodium nitrite is no greater than 0.5% by weight; wherein the sodium nitrite contains no greater than 0.4% by weight of sodium nitrate, no greater than 0.005% by weight of insoluble matter, no greater than 0.005% by weight of chloride, no greater than 0.01% by weight of sulfate, no greater than 0.001% by weight of iron, no greater than 0.01% by weight of calcium, no greater than 0.005% by weight of potassium, no greater than 0.05 ppm of mercury, no greater than 2 ppm of aluminum, no greater than 3 ppm of arsenic, and no greater than 0.003% by weight of selenium; wherein the sodium nitrite contains no greater than 10 ppm, no greater than 100 ppm, no greater than 500 ppm, no greater than 1000 ppm, or no greater than 5000 ppm of organic volatile impurities; wherein the total non-volatile organic carbon content in the sodium nitrite is no greater than 2.5 ppm, or no greater than 10 ppm; wherein the sodium nitrite has total aerobic count of microbial load of no greater than 100 CFU/g, has total yeast and mold count of no greater than 20 CFU/g, contains no greater than 0.25 EU/mg of bacterial endotoxins; wherein the sodium nitrite contains no less than 97% by weight and no greater than 101% by weight of sodium nitrite as measured by USP colormetric assay; and wherein the heavy metal content in the sodium nitrite is no greater than 10 ppm, for use in a method of treating, preventing or reducing the risk of a disease or condition associated with the cardiovascular system, wherein the disease or condition associated with the cardiovascular system is angina, claudication, peripheral artery disease, critical limb ischemia, tissue ischemia-reperfusion injury, intravascular thrombosis, an ischemic central nervous system event or a cardiovascular disease; or for use in a method of increasing blood flow to tissue, wherein blood flow to said tissue is decreased directly or indirectly by cardiopulmonary bypass, coronary disease, cardiac ischemia syndrome, angina, angioplasty, myocardial ischemia or tissue ischemia.