RICININE, the alkaloid of castor bean plants, is of interest since it is one of the very few natural products containing a nitrile group and since, as Leete and Leitz1 have shown, it is biogenetically derived from the vitamin, nicotinic acid. In our studies on the distribution and biogenesis of ricinine we have sought a semi-quantitative analytical method that would permit routine determination of ricinine in a large number of samples of plant tissue without tedious extraction and isolation procedures. Such a goal is hindered since ricinine is neutral and does not react with the usual ‘alkaloidal reagents’.