The alkaloids in the bark of Demerara greenheart have been investigated. Following treatment with methyl iodide, mixed amorphous alkaloids from the bark yielded a crystalline compound. Chemical and physical properties of the latter, which was also characterized as its chloride and picrate, as well as by an O-methyl derivative, led to a tentative formula of [C32H26O(N(CH3)2]2(OCH3)4OH]++I2-. This new alkaloid derivative is named rodiasine dimethiodide. © 1956, American Chemical Society. All rights reserved.