Winchia calophylla A. DC. (syn. Alstonia pachycarra Merrill et Chun) (Apocynaceae) (in Chinese "Pen Jin Shu"), natively abundant in the Yunnan province and Hainan island (China), represents one of two species belonging to the genus Winchia (1). The plant is used in the traditional medicine to treat cough, asthma, and acute and chronic bronchitis (2). From the ethanol extract of the roots of W. calophylla by the usual alkaloid isolation procedure, a mixture of compounds was isolated, from which four major components could be separated by column chromatography. Three of them were identified by their physical constants, spectral data, and acetylation products as N-demethylechitamine (1) (3), echitamine chloride (3), and loganine (4). A further alkaloid (2), C21H21H205, shows UV and JR spectral data similar to those of 1. The relative molecular mass however, is 16 amu higher. The intensive fragmentation (97%) of M — 16 at mlz 370 is typical for N-oxides. In the 13C-NMR spectrum, C-5 and C-21 bound to Nb, show large downfield shifts and C-6 and C-20 upfield shifts in relation to 1. These data indicate the structure of Nbdemethylechitamine N-oxide (2) which was confirmed by preparation of 2 from 1 by hydrogen peroxide oxidation.