Spirospermum penduliflorum collected in Ampanotoamaizina region and Strychnopsis thouarsii collected in Andasibe (both in the Eastern rain forest of Madagascar) were studied. Previous work on S. penduliflorum from Morondava region reported protoberberine alkaloid palmatine and clerodane diterpene columbin, but this study isolated bisbenzylisoquinoline (BBIQ) limacine from its roots (no alkaloid in leaves). From S. thouarsii, BBIQ fangchinoline, four aporphines (isocorydine, predicentrine, liriotulipiferine, N-methyllindcarpine), and morphinan alkaloid sinoacutine were identified from leaves, while fangchinoline and tetrandrine were from roots. Structures were established by spectral methods (mass spectra, 1D/2D NMR) and comparison with literature data. Chemotaxonomically, both genera belong to Cocculeae tribe, and S. thouarsii may be in Menisperminae subtribe. Contradictory results for S. penduliflorum may be due to environmental factors as they were collected in ecologically different regions.