As microbes develop resistance to various drugs, the treatment of infections becomes increasingly challenging, leading to prolonged illness, heightened severity of infections, elevated mortality rates, and increased healthcare costs. Essential oils are lipophilic and volatile mixtures of compounds that have gained attention in research for novel antimicrobial agents. Therefore, the present study evaluated the essential oil of Syzygium cumini leaves (EOSC) in order to prospect its antifungal and trichomonacidal activities. The essential oil from the leaves was extracted by steam distillation and analyzed by GC-MS. Antifungal activity was evaluated using the serial microdilution method. Additionally, the potential of the EOSC as an enhancer of fluconazole (FCZ) action was tested at subinhibitory concentrations. To assess anti-Trichomonas vaginalis activity, concentrations ranging from 15.6 to 500 μg/mL of EOSC were tested. Finally, the SwissADME platform was employed to analyze the physicochemical and pharmacokinetic characteristics of the major component of EOSC. The GC-MS analysis identified 94.24% of the components of EOSC, with α-pinene (51.11%) and nerol (8.25%) as major constituents. EOSC exhibited low antifungal activity against the evaluated Candida strains. However, the combination of EOSC and FCZ reduced the IC₅₀ against Candida krusei from 45.29 to 0.30 μg/mL. EOSC also demonstrated significant activity against T. vaginalis (IC₅₀ = 88.2 μg/mL). In silico prediction with α-pinene showed low toxic action and important physicochemical aspects for drug production. The essential oil of Syzygium cumini emerges as a promising candidate for the discovery of molecules with potential antifungal and anti-Trichomonas vaginalis applications.