Two new bisbenzylisoquinoline alkaloids, (+)-coccuorbiculatine A (2) and (+)-10-hydroxyisotrilobine (3), two new amidic aporphines, a mixture of (+)-laurelliptinhexadecan-1-one (6) and (+)-laurelliptinoctadecan-1-one (7), and one new protoberberine (-)-4-methoxy-13,14-dihydrooxypalmatine (8) have been isolated from the stems of Taiwanese Cocculus orbiculatus. The structures were established on the basis of extensive analysis of spectroscopic data and by comparison with known related metabolites. Cytotoxicity of the isolated compounds was examined toward HepG2, Hep3B, MCF-7, and MDA-MB-231 cancer cell lines. Alkaloids 1 and (-)-sinococuline (9) showed significant inhibitory activity against the target cell lines.