Abstract: Methods of synthesis and the properties of ammonium antimonylgluconate are reported. Addition of a solution of antimony trichloride in conc. aqueous gluconic acid to conc. ammonium hydroxide gave the said drug. It can also be prepared by the interaction of antimony triethoxide and ammonium gluconate. The antimony content of the product can be varied over wide limits (up to, say, 50% Sb), being dictated by the choice of the relative amounts of starting materials. Ammonium antimonylgluconate is readily soluble in water, practically insoluble in alcohol. Its aqueous solution is unstable towards heat, acids and bases. Direct titration of the untreated sample with iodine has been found unsuccessful, since the rate of oxidation of trivalent antimony to its pentavalent state is slow enough to give rise to shifting end points, presumably due to some protective action on the part of the gluconic acid residue. This behavior is to be contrasted with that of potassium antimonyltartrate (tartar emetic), where oxidation of antimony with iodine occurs instantaneously.