Potassium Sodium Tartrate is a double salt first prepared (in about 1675) by an apothecary, Pierre Seignette, of La Rochelle,France As a result the salt was known as Seignette's or Rochelle salts.
Traditionally, the salt is used to reduce the concentration of uric acid and the inflammation it causes in gout and related conditions. Half a teaspoon dissolved in warm water and taken twice daily lowers uric acid and the risk of kidney stones. Not recommended for people with high blood preassure or heart and kidney diseases.