Abstract: Objective To examine environmental hormone effects of flame retardant decholrane plus(DP).Methods The ovariectomized(OVX) female Wistar rats were randomly divided into six groups:OVX group,DP treatment groups(25,50,100 mg/kg),positive control group(estradiolE₂,50 mg/kg),and sham-operated group.The rats were treated once a day for 14 consecutive days and sacrificed on day 15;then,the blood samples were collected and uterus were weighed and stored under frozen.Serum-free triiodothyronine(FT₃),serum-free thyroxine(FT₄),and thyroid stimulating hormone(TSH) levels were measured with electrochemiluminescence immunoassay and uterine estrogen receptor α(Erα) mRNA expression was determined with real-time reverse transcription PCR(RT-PCR).Results Compared with the sham group,the uterine weight(0.112±0.035 g) and uterine/body weight ratio(0.072 ± 0.030) of the model group were significantly reduced and the expression of Erα mRNA level was significantly decreased(P<0.05).Compared with the model group,the uterine weight(0.419±0.059 g) and uterine/body weight ratio(0.186±0.143) of the high-dose DP group increased significantly and the expression of Erα mRNA in the uterus significantly increased,with significant differences(P<0.05).No statisticallly significant changes in serum FT₃,PFT₄,and TSH were observed in the rats with DP treatment.Conclusion DP has estrogenic effect but had no effect on serum thyroid hormone level in rats.