The major alkaloid of the leaves of Cissus rheifolia Planch. (Vitaceae) has been identified as a new quinolizidine, which has been named kayawongine and has been assigned the structure trans-2-(3,4-dimethoxyphenyl)-3-(4-methoxyphenyl)quinolizidine (2) by analysis of the spectral data. Also identified in the plant were the alkaloid cryptopleurine (1), the isomeric terpenoids vomifoliol (3) and ramalea aliene (4), and the major flavonoid vitexin (5). © 1983, American Chemical Society. All rights reserved.