Abstract The essential oil from the leaves of Siparuna thecaphora was analyzed by GC and GC/MS. Forty-six components were identified representing approximately 60% of the oil, among which oxygenated sesquiterpenes (27%), sesquiterpene hydrocarbons (18%) and linear oxygenated compounds (11%) were the major groups of constituents, with spathulenol (9.4%), 2-tridecanone (5.3%) and Î±-copaene (4.5%) being the main components. The oil exhibited bacteriostatic activity against Staphylococcus aureus and Mycobacterium smegmatis (MIC 250 (Î¼g/mL), but no larvicidal activity against Aedes aegypti.