E539 - sodium thiosulfate

Sodium thiosulfate (sodium thiosulphate) is a chemical and medication. As a medication it is used to treat cyanide poisoning and pityriasis versicolor.It is an inorganic compound with the formula Na2S2O3.xH2O. Typically it is available as the white or colorless pentahydrate, Na2S2O3·5H2O. The solid is an efflorescent (loses water readily) crystalline substance that dissolves well in water. It is also called sodium hyposulfite or "hypo".It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system.