Abstract: The antimonial chelates of ethylenediaminetetraacetic acid (Ⅱ, EDTA), propylenediaminetetraacetic acid (Ⅲ, PDTA) and nitrilotriacetic acid (Ⅳ, NTA) were reported to exhibit inhibitory activities on tumours, but the antimonial chelates of cyclohexane-1,2-diaminetetraacetic acid (Ⅰ) and β-hydroxyethylaminediacetic acid (Ⅴ) were found to be non-effective on the tumour growth in vivo. The relative stabilities of the amino polycarboxylic acid chelates of antimony were observed by Chue to be: Ⅰ>Ⅱ>Ⅲ>Ⅳ>Ⅴ. In this connection it was interesting to note that the antitumour activity seemed to be associated only with moderately stable chelates with antimony such as formed from PDTA-Sb and NTA-Sb. Since the introduction of nonchelating substituents in the chelating ligand might alter the basicity of the electron donor atom, or might prevent the most favourable metal-ligand orientation, it would be advisable to prepare the amino polycarboxylic acids (Ⅵ a—f), presumably having lower stability constant, related to nitrilotriacetic acid. The analogues of NTA (Ⅵ a m. p. 200—1℃; Ⅵ b m. p. 138—140℃; Ⅵ c m. p. 171—173℃; Ⅵ d m. p. 186—188℃; Ⅵ e m. p. 184—185℃; Ⅵ f m. p. 146—148℃) were prepared by the reaction of monochloroacetic acid with the dl-amino acids (alanine, isobutyric amino acid, α-aminobutyric acid, leucine, β-phenylalanine, aspartic acid, respectively). The aqueous reaction mixtures were passed through Zerolite 225-SO₃H to remove the sodium ion. The authors found that the use of resin was more convenient than the conventional method of acidification with inorganic acid. Difficulties were encountered in obtaining the amino polycarboxylic acids, Ⅵ, in crystalline. form in the presence of inorganic acids. In the case of Ⅵ f, the reaction mixture was passed through Amberlite IRA-401-OH to remove chloride ion, then through Zerolite 225-SO₃H to remove sodium ion. If the chloride ion was not removed, probably deamination took place (in the presence of hydrochloric acid) upon evaporation, and the reaction product was found not to be Ⅵ f. The amino polycarboxylic acids (Ⅵ a, c, d, e) on treatment with freshly precipitated antimonous acid or butyl antimonite according to Chue-Kyi's procedure, gave the corresponding antimonial chelates in which each antimonial atom combined with two molecules of chelating agents. Compound Ⅵ f failed to give a satisfactory chelate. Owing to low stability these antimonial chelates tend to decompose on recrystallization by conventional procedure. They were purified, as follows: the crude products were dissolved in large amount of warm water, the impurity was separated by filtration, and the filtrate was evaporated to dryness at low temperature under reduced pressure. Several repetitions of this procedure might be needed to give the analytical sample. Preliminary pharmacological tests revealed that the antimonial chelates of Ⅵ a (10 mg/kg), Ⅵ c (15 mg/kg) and Ⅵ e (20 mg/kg) inhibited the growth of Ehrlich ascites carcinoma of mice, but possessed no inhibitory action on sarcoma 180.