OBJECTIVE To study the effect of taurine on the reproductive toxicity damage induced by formaldehyde (FM) in adult male rats. METHODS Forty-eight SD adult male rats were equally randomized into a normal control, an FM poisoning (FMP), a taurine intervention (TI), and an TI+FMP group. The control rats were given normal diet and gavage of saline, the rats of the FMP group treated intraperitoneally with FM at 10 mg/kg qd alt, those of the TI group intragastrically with taurine at 100 mg/kg qd, and those of the TI+FMP group with both FM and taurine at the above doses. After 30 days of treatment, the blood of the abdominal cardinal vein of the rats was extracted for measurement of the levels of serum hormones, the body weight, testis weight and testicular coefficient obtained, the testis tissue subjected to HE staining, and the expressions of Bcl-2 and Bax determined by Western blot. RESULTS There were no statistically significant differences among the four groups of rats in the body weight, testis weight or testicular coefficient (P > 0.05). The rats in the FMP group showed obviously decreased testicular spermatogenic cells and disordered layers and loose structure of seminiferous tubules, which were basically restored to normal after taurine intervention. Compared with the normal controls, the animals of the TI group exhibited no significant abnormality, but those of the FMP group presented markedly reduced levels of serum T, LH and FSH (P < 0.05), and dramatically increased level of Gonadotropin-releasing hormone (GnRH) (P < 0.01). The levels of serum hormones were all significantly improved (P < 0.05) and that of the apoptotic protein Bax basically returned to normal (P < 0.05) after taurine intervention. CONCLUSIONS Taurine has a certain protective effect against male reproductive toxicity caused by formaldehyde.