Abstract The fruit fly Drosophila melanogaster is often utilized in genetic research, and in the last decades, it has become one of best organisms for studies of human diseases and toxicological research. Mercury chloride (HgCl2), the main representative of mercury compounds, is the target of numerous investigations, not only because of its intrinsic toxicity but also because it accounts for the toxicity of elemental mercury since the latter is converted to Hg+2 by oxidation. Eugenia jambolana Lam. Myrtaceae, known in Brazil as “jambolão”, is of great interest because of its medicinal applications, especially its leaves and fruits. The aim of this work was to characterize, by CG–MS, the chemical constituents of the essential oil of Eugenia jambolana and to evaluate its bioinsecticidal action in the Drosophila melanogaster model, as well as to determine the cytoprotective and chelating effect of the extract of E. jambolana. The results obtained here point to the potential of essential oils as a source in biological prospecting for bioinsecticides. Because of their biodegradability, essential oils can be important tools in the biological control of pests. The results demonstrated that the extract has an allelopathic effect on lettuce seeds and that its interaction with mercury chloride allows a greater growth of the radicle and plumule of Lactuta sativa seedlings, showing that this plant can provide an alternative solution to the problem of contamination by heavy metals, besides having cytoprotective potential and moderate chelating activity.