D.P.D.Tartaric acid is a muscle toxin, which works by inhibiting the production of malic acid, and in high doses causes paralysis and death.[citation needed] The minimum recorded fatal dose for a human is about 7.5 grams/kg.[citation needed] Given this figure, it would take over 500g to kill a person weighing 70kg.

Important derivatives of tartaric acid include its salts, Cream of tartar (potassium bitartrate), Rochelle salt (potassium sodium tartrate, a mild laxative) and tartar emetic (antimony potassium tartrate).

A rarely occurring optically inactive form of tartaric acid, DL-tartaric acid is a 1:1 mixture of the levo and dextro forms. It is distinct from mesotartaric acid and was called racemic acid (from Latin racemus - "a bunch of grapes").

The word racemic later changed its meaning, becoming a general term for 1:1 enantiomeric mixtures - racemates. ­­ Tartaric acid is used to prevent Copper(II) ions from reacting with the hydroxide ions present in the preparation of copper(I) oxide. Copper(I) oxide is a reddish brown solid, and is produced by the reduction of a Cu(II) salt with an aldehyde, in an alkaline solution.

Naturally occurring tartaric acid is chiral, meaning that it has molecules that are non-superimposable on their mirror-images. It is a useful raw material in organic chemistry for the synthesis of other chiral molecules.