Two new monomeric and two new dimeric drimane sesquiterpenes, cinnamacrins A-C (1-3) and cinnafragrin D (4), along with bemadienolide (5), capsicodendrin (6), cinnamodial (7), cinnamolide (8), isopolygodial (9), and delta-tocotrienol (10), were isolated from Cinnamosma macrocarpa. The structures of the new compounds were determined by physical, chemical, and spectroscopic evidence. Capsicodendrin (6) and/or cinnamodial (7) are the major compounds in C. fragrans and C. macrocarpa, which are both widely used in Malagasy traditional medicine. The cytostatic activity as well as alpha-glucosidase inhibition and antiviral activities of the major constituents 6 and 7 and the compounds previously isolated from C. fragrans were evaluated.