Abstract Potassium clupanodonate has been oxidised with potassium permanganate in alkaline solution under cooling. Among the oxidation products, propionic, acetic and succinic acids have been separated. Also the presence of malonic acid is indicated. Of these compounds acetic acid is believed to be formed by a further degradation of malonic acid, and consequently the above results show that the respective groups jointed by the ethylenic linkings in clupano-donic acid are CH3·CH2·CH=, =CH·CH2·CH=, three of =CH·(CH2)2·CH=, and =CH·(CH2)2·COOH, provided the terminal group containing the carboxyl group is assumed to be =CH·(CH2)2·COOH. The results of the present experiment agree fully with those obtained in tile previous experiments of the ozonolysis of amyl clupanodonate and the permanganate oxidation of methyl clupanodonate in acetone solution.