Introduction: Studies prove that the use of medicinal plants is a custom carried out by man since ancient times, the evolution of the pharmaceutical industry makes more people consume more natural products. Currently, we can observe that mouthwashes containing natural compounds have shown a growth in demand in the markets and in the professional community. Objective: The present study aims to carry out the chemical characterization and microbiological potential of Piper mikanianum (Kunth) Steud essential oil (EOPm), providing data that allows the development of a low‐cost mouthwash formulation aimed at vulnerable communities. Methods: The evaluation of the antibacterial activity and modulator of bacterial resistance was performed by the microdilution method to determine the minimum inhibitory concentration (MIC). The chemical components were characterized by gas chromatography coupled to mass spectrometry, identified 28 constituents, in which Safrole Phenylpropanoid is the major compound, representing 72.6 % of the total composition, followed by α‐pinene (10.7 %), Limonene (2 %), β‐caryophyllene (2 %), E‐nerolidol (1.9 %), spathulenol (1.3 %) and camphene (1.1 %). Results: The EOPm showed a MIC minimum inhibitory concentration≥1024 μg/mL for all bacterial strains used in the tests. When the EOPm modulating activity combined with chlorhexidine, mouthwash, ampicillin, gentamicin and penicillin G was evaluated against bacterial resistance, the oil showed significant synergistic activity, reducing the MIC of the products tested in combination, in percentage between 20.6 % to 98 .4 %. Conclusions: We recommend the expansion of tests with greater variation of EOPm concentration combinations and the products used in this study, as well as toxicity evaluation and in vivo tests, seeking the development of a possible low‐cost mouthwash formulation accessible to the most vulnerable population.