Emerging evidence demonstrates that dual inhibition of glycolysis and mitochondrial function represents a potent anticancer strategy. Here, we report that Ditrioxzin (DTO), a synthetic ent-kaurane diterpenoid analog, selectively disrupts mitochondrial redox homeostasis by targeting peroxiredoxin 3 (Prx3) to induce hydrogen peroxide (H2O2) accumulation, thereby depolarizing mitochondrial membrane potential (MMP) and impairing oxidative phosphorylation (OXPHOS) in gastric cancer cells. DTO synergized with the glycolytic inhibitor 2-deoxy-d-glucose (2-DG) to deplete ATP through dual metabolic blockade. In vitro studies revealed that DTO exerted selective cytotoxicity against gastric cancer cells (IC50 3.82-6.10 μM) but spared normal gastric epithelial cells (GES-1). Mechanistically, DTO directly bound Prx3, elevating H2O2 levels (>3-fold at 8 μM), oxidizing mitochondrial peroxiredoxins, and triggering redox-dependent mitochondrial dysfunction. Combined DTO/2-DG treatment promoted ATP depletion and apoptosis (69.6 % vs 24.1 % DTO alone) via ROS-dependent pathways, an effect abrogated by N-acetylcysteine. In vivo, DTO (10 mg/kg) and 2-DG (500 mg/kg) synergistically suppressed tumor growth (66 %, P < 0.001) in xenograft models without body weight loss or histopathological changes in kidney/heart. Our findings establish DTO as a novel Prx3-targeted agent that synergizes with 2-DG to induce metabolic crisis, providing a high-safety-profile therapeutic strategy for gastric cancer.