A new naphthoquinone, 6-methoxy-7-hydroxy-a-dunnione (1), along with four known compounds (2, 4, 10, and 11) were isolated from Sinningia canescens (Mart.) Wiehler tubers, while S. warmingii (Hiern.) Chautems furnished eight known compounds (3-10). The known compounds were identified as 7-hydroxy- α-dunnione (2), lapachenole (3), tectoquinone (4), 7-methoxytectoquinone (5), 1-hydroxytectoquinone (6), 7-hydroxytectoquinone (7), aggregatin C (8), aggregatin D (9), halleridone (10), and cedrol (11). In addition, S. canescens yielded a volatile fraction, which was analyzed by GC/FID and GC/MS. This fraction was constituted mainly by sesquiterpene hydrocarbons (82.6%). The major components were β-santalene (14.6%), β-cedrene (10.4%), and trans-cadina-1(6)-4-diene (10.0%).