To evaluate the in vitro antibacterial effect of essential oil of Piper angustifolium (Matico) on strains of methicillin resistant Staphylococcus aureus and Pseudomonas aeruginosa. MATERIALS AND METHODS: Experimental study of the antibacterial effect of concentrations of 25%, 50%, 75% and 100% of the essential oil of Piper angustifolium (Matico) on strains of Staphylococcus aureus methicillin resistant and Pseudomonas aeruginosa was used as control Vancomycin 500 mg for methicillin-resistant Staphylococcus aureus and Imipenem 500 mg for Pseudomonas aeruginosa. Disc diffusion method and minimal inhibitory concentration (MIC) were used. The Kruskal-Wallis nonparametric variance analysis test and the paired comparison test were performed using homogeneous subsets. Both with a level of significance P <0.05. Results: Piper angustifolium showed antibacterial activity on methicillin-resistant S...