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Lippia gracilis Schauer (Verbenaceae) is an aromatic plant widely used in folk medicine in the Brazilian semi-arid region. This work aims at evaluating the anti-microbial activity of essential oils from the leaves of L. gracilis (EOLG) when associated with commercial antibiotics against bacterial resistance. The essential oil obtained by hydrodistillation has 38 chemical constituents with thymol (44.4%), carvacrol (22.2%), p-cymene (6.2%) and alpha-pinene (5.6%) as major constituents. Microbiological assays were conducted by direct and gaseous contacts. We demonstrated that EOLG has significant synergism with all antibiotics tested. EOLG decreased the minimal inhibitory concentration of the aminoglycosides and improved their zone of inhibition more than 300% against Staphylococcusaureus and 270% against Pseudomonasaeruginosa. These results demonstrate that natural substances present in EOLG have the capacity to modulate bacterial resistance and can be used as an adjuvant therapy against multi-resistant microorganisms such as S. aureus, Escherichia coli and P. aeruginosa.