The composition and antimicrobial activities of the essential oil of Aconitum tanguticum from the southern part of Gansu Province of China were investigated. The essential oil of aerial parts was obtained by hydrodistillation with a 0.7% （v/w） yield. The chemical composition of the essential oil was analyzed by gas chromatography-mass spectrometry （GC-MS） method. Thirty-five compounds were characterized in the oil, which were mainly monoterpenoids （41.7%） and sequiterpenoids （12.7%）. The main compounds in the oil were （-）-tran-pinecarvyl acetate （15.6%）, heptane （14.88%）, cineole （6.82%）, 3-pinanone （3.64%）, pinocamphone （3.34%）, cadinol （2.93%）, and cubenol （2.33%）. These compounds are identified for the first time in Aconitum tanguticum. The antimicrobial activities of the oil were evaluated against 9 bacteria strains, 1 yeast strain and 3 fungi strains using agar diffusion and broth microdilution methods. It showed strong inhibition against Fusarium semitectum and methicillin-resistant Staphlococcus aureus, low activity against Escheriehia eoli, but no effect against Epidermophyton floccosum. Its MIC values ranged from 0.125 5.000 mg/mL. Thirty-five compounds are newly identified in Aconitum tanguticum.
