In a previous publication (Coulsen and Griffin, 1967) the nature and distribution of alkaloids of the aerial parts of D. myoporoides were reported. Other investigations into the alkaloids of D. myoporoides have been confined to the aerial parts since they constitute the commercial source of the mydriatic alkaloids. The roots are of particular interest as they have been shown to be the site of alkaloid synthesis in plants of the Solanaceae (Warren Wilson, 1952; Peacock, Leyerle and Dawson, 1944; Loftus Hills, Trautner and Rodwell, 1946; Steinegger, 1954). Thus an investigation of the root alkaloids was undertaken. An alkaloidal extract of the young root wood of Duboisia myoporoides contained tropine, valtropine, hyoscyamine and valeroidine. Tropine was the major alkaloid. From D. myoporoides young root bark was isolated scopolamine, atropine, tropine and apohyoscine. Extracts were made of root wood and root bark of mature trees. Hyoscyamine, scopolamine, apohyoscine, tropine and tetramethylputrescine were obtained after chromatographic fractionation of the old root wood extract. Similarly hyoscyamine, tetramethylputrescine, tropine, scopolamine, valtropine and apohyoscine were constituents of the old root bark.