This study was designed to determine the effects of daily oral administration (250mg/kg) of the hydroalcoholic extract of Fumaria parviflora (FP) for 14days on the sperm parameters, oxidative stress parameters, serum testosterone levels, expression of Bax and Bcl-2 genes, and apoptosis index of germ cells after testicular torsion-detorsion (ischaemia-reperfusion, IR) injury model in rats. Twenty-eight adult male Wistar rats were divided randomly into four groups of seven each: sham operation, torsion-detorsion (TD), TD plus the hydroalcoholic extract FP (TDFP) and only FP without TD application (FP). Testicular torsion was created by rotating the left testis 720° in a counterclockwise direction; then, after 4hr, detorsion was performed. The Johnson's score, mean seminiferous tubule diameter (MSTD) and height (thickness) of seminiferous tubule epithelium (HST) were significantly increased in TDFP and FP groups as compared to TD group. The gene expression of Bcl-2, level of serum testosterone hormone and antioxidant parameters-GPx and SOD-were significantly higher in TDFP and FP groups than TD group. The index of apoptosis, the gene expression of Bax and the level of MDA were significantly higher in TD group than TDFP and FP groups. Therefore, F.parviflora could decrease oxidative stress induced by testicular torsion-detorsion.