Sodium nitrite is widely used in the food industry as a preservative, particularly in cured meats like bacon, ham, and sausages. It prevents the growth of harmful bacteria, such as Clostridium botulinum, which can cause botulism. Additionally, it helps maintain the pink color of meat and enhances flavor.

In industrial applications, sodium nitrite acts as a corrosion inhibitor in cooling systems and metalworking fluids. It protects metal surfaces from rust and degradation, extending the lifespan of machinery and equipment. It is also employed in water treatment to remove certain toxins and in the rubber industry to accelerate vulcanization.

It is utilized in the production of dyes and pharmaceuticals, where it serves as a reagent in various chemical reactions, such as diazotization.

In emergency medicine, sodium nitrite is an antidote for cyanide poisoning, helping to convert cyanide into a less toxic compound that the body can eliminate. It is also used to treat methemoglobinemia, a condition where blood cannot transport oxygen efficiently.

However, due to its toxicity at high doses, its use is strictly regulated in food and other applications to ensure safety.