AbstractThe essential oil from the leaves of Callistemon speciosus (Sims) DC. grown in Cuba was isolated by hydrodistillation and analyzed by gas chromatography (GC) and chromatographyâmass spectrometry (GCâMS). Eighty-eight compounds were identified and quantified, accounting for 99.8% of the total composition. The major components were 1,8-cineole (57.0%) and Î±-terpineol (20.4%). The in vitro antibacterial activity of the essential oil was studied against five bacteria strains (Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Bacillus subtilis and Escherichia coli) using the disc diffusion method. All the bacteria tested were susceptible to the C. speciosus essential oil.Keywords: Callistemon speciosusessential oilgas chromatographyâmass spectrometryantibacterial activity1,8-cineoleÎ±-terpineol