Potassium nitrate (KNO3) is a crystalline ionic salt of potassium and nitrate ions. It is a common oxidizer and is used in the production of solid propellants, explosives, fertilizers, and medicine.

Potassium Nitrate is a white to dirty gray crystalline solid that is water soluble and noncombustible. It is the main component of the nitrate ion in nitrate saltpeter.

In its crystalline form it is highly toxic and can be fatal to human beings if inhaled or ingested. Exposure to potassium nitrate can cause burns on the skin or eyes, diuresis, headache, nausea, and methemoglobinemia.

It is used in the manufacture of fireworks, matches, glass, ceramics, candle wicks and rocket propellants. It is also used in pickling meats and as an oxidizer.

The toxicity of potassium nitrate depends on the cation and anion. The cation of potassium nitrate can be changed by exposure to other chemicals and by the activity of certain microflora in the mouth and the gastrointestinal system. The nitrate ion is reduced to nitrite by the action of bacteria in the saliva and gastrointestinal tract.

In addition, nitrates are absorbed into the blood and transported to various organs throughout the body. The absorption of nitrates is very rapid, compared with other inorganic ions such as sodium or magnesium. The amount of nitrate absorbed into the blood is much less than that excreted in the urine, but is still substantial. The rate of distribution of nitrates throughout the body is dependent on the blood flow to those organs.