Used primarily in the food industry as a preservative, especially in cured meats like bacon, ham, and sausages, to prevent bacterial growth, including Clostridium botulinum. It helps maintain the pink color of meat and contributes to flavor development during curing.

Also employed in industrial applications such as corrosion inhibition in cooling systems and metal plating processes, and as a reagent in organic synthesis, particularly in diazotization reactions for producing azo dyes and pharmaceuticals.

Additionally, it serves in some medical formulations for its vasodilatory effects, such as treating angina, though its use has declined in favor of safer alternatives. In laboratories, it is used for analytical procedures involving nitrite detection.

Caution is advised with high doses, as it may cause methemoglobinemia poisoning, particularly in children and individuals with certain health conditions.