Background and Aim: Baccharis trinervis (Lam.) Pers and Vernonia cinerea (L.) Less are used in traditional medicine in the treatment of several infectious diseases, including typhus, cholera, hepatic diseases, malaria, pulmonary, skin infections and conjunctivitis. The present research aimed to investigate the antimicrobial activity of extracts from B. trinervis and V. Cinerea. We compared the results obtained in this study with the folkloric medicinal use of these species. Materials and Methods: Antibacterial and antifungal tests were performed using the disc-diffusion method.  The tested extracts were obtained by partitioning, with solvents of increasing polarity of the residual aqueous layer from the methanol-aqueous extracts obtained from the powdered plant material. The use of the examined species in the popular pharmacopoeia was investigated from a wide literature review. Results: The results of this study revealed that V. cinerea had the broadest antimicrobial effect. The most polar extract, obtained by partition with n-butanol, was active against the Gram + bacteria Staphylococcus aureus and Bacillus cereus and the fungal pathogens Fusarium oxysporum and Aspergillus Niger. On the other hand, the activity of B. trinervis was evidenced only against B. cereus in the extract obtained by partition with the solvent of lower polarity, CH2Cl2. Conclusion: The present study indicated that V. cinerea and B. trinervis contains metabolites that exhibit varying degrees of antimicrobial activity. Moreover, our findings confirm that Vernonia cinerea is a promising source of biologically active compounds potentially useful for the treatment of infectious diseases. In fact, the use of this plant in folklore medicine has been validated.