Four new alkaloids, rubemternonone 111, tuberosternono1 121, sternoamide 131, and tuberosternospironine 141, together with two known alkaloids, tuberosternonine and didehydrotubenxternonine, were isolated from the roots of Stemona tuberosa (Stemonaceae). Their structures were elucidated by ir, ms, and 1D- and 2D-nmr techniques including difference nOe spectra and homonuclear and heteronuclear spectral analyses. The roots of Stemona tuberosa Lour. and related Stemona species (Stemonaceae) are used in Chinese traditional medicine as anticough agents and insecticides. Eleven alkaloids have been isolated from the roots so far; the structures of five were determined by X-ray analyses, and the structures of stemotinine and isostemotinine were first determined by us with spectral analyses (1). On this basis a series of new Stemona alkaloids have been discovered, and their structures were elucidated by 2D nmr techniques (2,4, 5, 7-9). As a part of continuing studies on Stemona plants, we report four new alkaloids, tuberostemonane 111, tuberostemonolE21, stemoamide 131, and tuberostemospironine 141 together with two known alkaloids, tuberostemonine 157 and didehydrotuberostemonine 167 separated from S. tuberosa collected in Guangdong Province, China.