Phyllanthus fraternus (PF) (Euphorbiaceae) is used in ancient Indian traditional phytomedicine to treat various human diseases including hepatic and renal disorders. The present study was designed to investigate the protective effect of PF aqueous extract against bromobenzene-induced mitochondrial dysfunction in rat kidney, compared with vitamin E used as positive control. Male Wistar rats divided into six (A-F) groups and the experimental animals were administered bromobenzene with or without prior administration of PF extract or vitamin E. Animals were sacrificed and the kidneys obtained for studying mitochondrial function and histopathology. Administration of bromobenzene caused significant changes, including decrease in the mitochondrial respiration and P/O ratios, an increase in lipid peroxidation and protein oxidation, and a decrease in the activities of antioxidant enzymes (catalase, superoxide dismutase, glutathione reductase, and glutathione peroxidase) in mitochondria with significant histopathological changes in the kidney. However, prior administration of the PF extract showed significant protection against bromobenzene induced renal damage by reversing all above parameters. Mitochondrial dysfunction induced by bromobenzene was protected much better with the PF extract than with vitamin E. These results suggested that the Phyllanthus fraternus extract is an efficient armament against nephrotoxicity induced by bromobenzene. The present study was designed to investigate the protective effect of PF aqueous extract against bromobenzene-induced mitochondrial dysfunction in rat kidney. compared with vitamin E used as positive control. Male Wistar rats divided into six (AF) groups and the experimental animals were administered bromobenzene with or without prior administration of PF extract or vitamin E. Animals were sacrificed and the kidneys obtained for studying mitochondrial function and histopathology. Administration of bromobenzene caused significant changes, including decrease in the mitochondrial respiration and P / O ratios, an increase in lipid peroxidation and protein oxidation, and a decrease in the activities of antioxidant enzymes (catalase, superoxide dismutase, glutathione reductase, and glutathione peroxidase) in mitochondria with si However, prior administration of the PF extract showed significant protection against bromobenzene induced renal damage by reversing all above parameters. Mitochondrial dysfunction induced by bromobenzene was protected much better with the PF extract than with vitamin E. These results suggested that the Phyllanthus fraternus extract is an efficient armament against nephrotoxicity induced by bromobenzene.