A chemical compound composed of elements hydrogen, potassium, oxygen and sulfur with a chemical formula of HKO3S. Sometimes referred to as potassium bisulphite solution or potassium hydrogen sulfite.

Commonly used as a sterilizing agent during the production of alcoholic beverages due to antimicrobial properties. May be used both to sterilize equipment and also as an ingredient in the production of wine.

Generally classified as an eye, skin and respiratory irritant.