The study evaluated the antioxidant, negative geo-taxis, survival, and reproductive effects of Eucalyptus globulus, bark and leaf extracts in Drosophila melanogaster. This method of evaluation could help determine the potential of Eucalyptus globulus as a natural intervention against age-related decline, oxidative stress and overall health. Despite numerous studies on Eucalyptus globulus, its impact on specific functional parameters like survival, negative geotaxis, antioxidant enzymes and reproductive capacity in Drosophila melanogaster remains largely unexplored. It is against this background that the study was undertaken to investigate the antioxidant, the negative geotaxis, survival and the reproductive capacity of the plant in Drosophila melanogaster. The LC₅₀ values obtained were 328 mg/10 g diet for the leaf extract and 180 mg/10 g diet for the bark extract, suggesting a wider safety margin in the leaf when related to the bark. Chronic exposure to the flies revealed the relative safety of the leaf and potential moderate toxicity of the bark. Negative geotaxis was unaffected by the leaf extract but significantly reduced in bark-treated flies. Both extracts suppressed fecundity, although the bark caused stronger inhibition. Biochemical analysis of the safer extract (leaf) revealed increased total protein and catalase activity with the leaf extract, alongside reduced glutathione-S-transferase (GST) activity, suggesting adaptive antioxidant responses to moderate oxidative stress. In conclusion, while the bark extract showed potential moderate toxicity, impaired locomotion and reduced reproductive capacity, the leaf extract demonstrated relative safety, sustained locomotor activity, and enhanced reproductive capacity at lower concentrations. Therefore, Eucalyptus globulus leaf stands as a safer candidate for pharmacological and nutraceutical exploration, offering antioxidant resilience without compromising fundamental biological functions.