The purpose of the thesis following thesis was to determine the effect of the essential oil of Ocimum basilicum L. on the growth of Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa in Vitro. The essential oil was obtained by the method of steam distillation. The effect of the essential oil was evaluated by the modified Kirby - Bauer diffusion method using concentrations of 10, 20, 40 and 60μL / mL and Vancomycin and Ciprofloxacin as positive control for Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa respectively, a standardized inoculum with the turbidity pattern of 0.5 of the Mcfarland Nephelometer was planted by the technique of surface sowing. The readings were performed, the inhibition halos in (mm) were found in the concentration of 10 μL / ml of essential oil that inhibits the growth of Staphylococcus aureus ATCC 25923 by 50% as the concentration increases...