Nine terpenoids were isolated from the leaves and flowers of Salvia amarissima, including a new acylated diterpenoid glucoside, amarisolide F (1), a new neo-clerodane diterpenoid, amarissinin D (2), which was isolated as an acetyl derivative (2a), and four known diterpenoids. The structure of amarisolide F (1) was elucidated by NMR and MS data analyses, as well as its methanolysis products 7 and 8, which also constituted new diterpenoids, named amarissinin E and 8- epi-amarissinin E, respectively. The absolute configuration of compound 7 was established by single-crystal X-ray diffraction. The cytotoxicity and anti-MDR effect of 1 in three phenotypes of the MCF-7 cell lines were assayed. Compound 1 was 2-3.6-fold more active than amarissinins A (3) and B (4), but several orders of magnitude less active than teotihuacanin (6) and reserpine.