This study evaluated the antimicrobial, antioxidant and toxicity activity of essential oils (EOs) of Hymenaea courbaril L. var. courbaril bark and Syzygium cumini (L.) Skeels leaves. The EOs were extracted by hydrodistillation and chemically characterized by gas chromatography coupled to mass spectrometry (GC/MS). The ABTS and DPPH assay were used to evaluate antioxidant activity. For the toxicity assay, lethality was evaluated against Artemia salina Leach. For the antimicrobial assay, the method of Disc Diffusion and Dilution in Broth was applied to obtain the minimum inhibitory concentration and minimum bactericidal. The major constituent of the EO of H. courbaril was β-ocimene (23.33%) and the EO of S. cumini was isocaryophyllene (18.01%). Both OE showed relevant antioxidant activity and low toxicity against Artemia salina. The EOs showed bactericidal activity against E. coli, S. aureus, P. aeruginosa, Salmonella sp., B. cereus and P. mirabilis. The results obtained are encouraged by the potential use of the OE's studied in the control and fight of pathogenic microorganisms.