Five Brazilian plant extracts from Pimenta pseudocaryophyllus, Erythrina speciosa, Tephrosia toxicaria, Inga marginata and Cassia leptophylla found in Paraná State and currently used in folkloric medicines, were assayed for antibacterial, antifungal and toxic activities. The antibacterial and anti-yeast activities were assessed by a diffusion assay on Gram (+) bacteria (Bacillus subtilis and Staphylococcus aureus), Gram (-) bacteria (Escherichia coli and Pseudomonas aeruginosa), and the yeasts (Candida albicans, Candida krusei, and Candida tropicalis). The extracts were also tested against the phytopathogenic fungi (Lasiodiplodia theobromae, Botryosphaeria ribis, Botryosphaeria rhodina, and Fusarium verticillioides) by growth inhibition using Captan™ as control. The toxicity was evaluated in Artemia salina through LC 50 (50% median lethal concentration) using Probit analysis. P. aeruginosa was inhibited by P. pseudocaryophyllus stems, E. speciosa and C. lephophylla leaves. E. coli by P. pseudocaryophyllus stems, B. subtilis by C. leptophylla leaves, and T. toxicaria roots. C. albicans by P. pseudocaryophyllus stems and E. speciosa leaves, while C. krusei by P. pseudocaryophyllus stems, and C. tropicalis by P. pseudocaryophyllus leaves, E. speciosa leaves and I. marginata leaves. E. speciosa and P. pseudocaryophyllus leaf extracts also inhibited all the phytopathogenic fungi examined. T. toxicaria roots showed stronger toxicity towards A. salina.