Abstract The chemical composition of Minthostachys verticillata oil from Argentina was studied. Forty-five compounds, accounting for 94.2% of the oil, were identified by GC and GC/MS analyses. The oil was characterized by a high amount of mono-terpenes (91.6%), of which 73.6% were represented by oxygenated compounds. Pulegone (37.8%) and menthone (29.2%) were the main constituents. A preliminar antibacterial screening was carried out, resulting in an inhibitory activity of the oil on four Gram (+) and Gram (-) bacterial strains