This work is dealing with the phytochemical investigations of Vietnamese medicinal Plants Tabernaemontana bovina Lour (Apocynaceae) and Fissistigma bracteolatum Chatterjee (Annonaceae). From the leaves of T. bovina 14 indol alkaloids were isolated and their structures elucidated. Among them six compounds are new (3-oxomehranine, 14α,15β-dihydroxy-N-methylaspido-spermidine, methylenebismehranine, tabernaebovine, tabernaemontabovine, tabernaemontavin), and eight are known (hecubine, (-)-mehranine, (-)-ibogaine, ibogaline, 19-epi-voacristine, 19-epi-isovoacristine, 19-hydroxyconopharyngine, pedunculine). From the leaves of F. bracteolatum 11 compounds were isolated. There are two known compounds (2-hydroxy-3,4,6-trimethoxychalcone, 5,7,8-trimethoxyflav-3-ene), five new chalconoids (2-hydroxy-3,4,6-trimethoxychalcene, 2-hydroxy-3,4,6-trimethoxy-dihydrochalcone, 2’-hydroxy-3’,4’,6’-trimethoxydihydrochalcone, 2’-hydroxy-3’,4’,6’-trimethoxy-β’-methoxychalcane, 2’-hydroxy-3’,4’,6’-trimethoxy-β’-ethoxychalcane) and four Fissistigmatins A-D, one new group of natural products: flavenes bearing sesquiterpens. These compounds were isolated by column chromatography on silica gel or reversed-phase RP-8 and preparative thin layer chromatography. Their structural elucidations were done by combined applications of spectroscopic methods (IR, UV, MS, especially 1D and 2D NMR). The absolute configuration was determined by X-ray or CD spectra.