In order to validate the Bumelia sartorum Mart., Sapotaceae, traditional use for infection diseases, this study evaluates the antibacterial activity of the stem bark fractions against methicillin-sensitive (MSSA) and methicillin-resistant (MRSA) Staphylococcus aureus strains by using the agar dilution method and reported as MIC (minimal inhibitory concentration). In addition, the DPPH scavenging activity of these fractions was measured and the chemical composition and acute toxicity of the active fraction were also determined. The ethyl acetate (EtOAc) extract was chemically analyzed by LC/MS, direct ionization APCI/MS, ¹H NMR and 13C-NMR. All fractions, except butanol extract, presented high antioxidant activity, especially the methanol and the EtOAc extracts, which showed EC50 values (5.67 and 5.30 µg/mL, respectively) considerably lower than the Gingko-standard EGb 761® (38.58 µg/mL). The antibacterial activity against S. aureus strains was observed in EtOAc (MIC 256-512 µg/mL), which showed a very low toxicity. The chemical study of this fraction revealed the abundant presence of polyphenolic compounds. The antibacterial and antioxidant activities reported in this paper for EtOAc extract from B. sartorum and the low toxicity of this fraction opens the possibility that it could be helpful for the developing of new antibacterial agents for treating S. aureus infections.