A new 3beta-O-vanilloyl-taraxerol, microcisin (1) and eight known compounds, 3beta-taraxerol acetate (2), 3beta-taraxerol (3), cholest-4-en-3-one (4), cholest-4-en-6beta-ol-3-one (5), beta-sitosterol (6), 7-hydroxycadalene (7), mellein (8) and vanillin (9), were isolated from the roots of Microcos tomentosa. The structures were determined by extensive analysis of their spectroscopic data. All isolated compounds were evaluated for their cytotoxicity against KB and HeLa cells.