There is provided a method for purifying an organic polycarboxylic acid wherein the amounts of organic monofunctional impurities associated therewith are substantially reduced, which method comprises conducting steam distillation of a stream comprising said polycarboxylic acid. In one embodiment of the method, a reactor effluent comprising a polycarboxylic acid is introduced into a crystallization zone, said effluent being subjected to crystallization and steam distillation coextensively in said crystallization zone.The method of the present invention may be used suitably to purify 1,4-cyclohexanedicarboxylic acid in a reactor effluent from the hydrogenation of a terephthalic acid by reducing the amounts of 4-methyl-1-cyclohexanecarboxylic acid and cyclohexanecarboxylic acid, as well as other organic impurities, contaminating the dicarboxylic acid.There is also provided the polycarboxylic acid purified by the method of the present invention.