Knowledge of medicinal plants is often the only therapeutic resource of many communities and ethnic groups. "Erva-baleeira", Cordia verbenacea DC., is one of the species of plants currently exploited for the purpose of producing a phytotherapeutic product extracted from its leaves. In Brazil, its major distribution is in the region of the Atlantic Forest and similar vegetation. The crude extract is utilized in popular cultures in the form of hydroalcoholic, decoctions and infusions, mainly as antimicrobial, anti-inflammatory and analgesic agents. The aim of the present study was to establish a chemical and comparative profile of the experimental antibacterial activity and resistance modifying activity with ethnopharmacological reports. Phytochemical prospecting and HPLC analysis of the extract and fractions were in agreement with the literature with regard to the presence of secondary metabolites (tannins and flavonoids). The extract and fraction tested did not show clinically relevant antibacterial activity, but a synergistic effect was observed when combined with antibiotic, potentiating the antibacterial effect of aminoglycosides. We conclude that tests of antibacterial activity and modulating the resistance presented in this work results confirm the ethnobotanical and ethnopharmacological information, serving as a parameter in the search for new alternatives for the treatment of diseases.