2,3-dihydroxybutanedioic acid is a tetraric acid that is butanedioic acid substituted by hydroxy groups at positions 2 and 3. It has a role as a human xenobiotic metabolite and a plant metabolite. It is a conjugate acid of a 3-carboxy-2,3-dihydroxypropanoate

Tartaric acid is commonly used in the manufacture of pharmaceuticals, mordants, tanning agents, etc., and also as a reagent for resolving racemic basic compounds.It is also used as an acidulant in food additives, with a sour taste superior to that of malic acid, lactic acid, etc.Several of its salts have important applications. For example, potassium sodium tartrate is used in the laboratory to prepare Fehling's reagent for identifying aldehyde functional groups in organic molecular structures.Its potassium sodium salt is also known as Rochelle salt. Its crystals polarize under pressure and generate a potential difference across the two end surfaces (piezoelectric effect), which can be used to make piezoelectric components for receivers and pickups in radio and wire broadcasting.In medicine, antimony potassium tartrate (commonly called tartar emetic) is used to treat schistosomiasis.