As nanotechnology gains popularity in medicine, there is a growing concern that small nanoparticles (NPs) could accumulate and penetrate deep into the human body, posing potential risks to various organs. To ensure safe usage and assess potential hazards, it is crucial to conduct a toxicological evaluation of ZnO NPs on human organs such as the kidney. The present study involved the synthesis of ZnO NPs by using the hydrothermal method. Pure and crystalline phase was confirmed by X‐ray diffraction (XRD). The SEM images displayed less agglomerated surface morphology, implying that the NPs were distributed relatively evenly and exhibited a plate‐like shape. Two pathogenic fungi Fusarium incarnatum and Aspergillus niger were isolated from the capsicum and tomato, respectively, and identified through morphological and molecular analysis. The antimycotic property of synthesized ZnO NPs were examined against Fusariumincarnatum (MT682502) and Aspergillus niger (MT675916) and showed decreased microbial growth after 9 days of incubation. The toxicological evaluation of ZnO NPs on a human embryonic kidney (HEK293) cell line showed 88% cell viability with 10 μg/ml, leading to the safe use of ZnO NPs.