Pyrithione is the common name of an organosulfur compound with molecular formula C5H5NOS, chosen as an abbreviation of pyridinethione, and found in the Persian shallot. It exists as a pair of tautomers, the major form being the thione 1-hydroxy-2(1H)-pyridinethione and the minor form being the thiol 2-mercaptopyridine N-oxide; it crystallises in the thione form. It is usually prepared from either 2-bromopyridine, 2-chloropyridine, or , and is commercially available as both the neutral compound and its sodium salt. It is used to prepare zinc pyrithione, which is used primarily to treat dandruff and seborrhoeic dermatitis in medicated shampoos, though is also an anti-fouling agent in paints.