【Abstract】 We first report the effect of a compound EP-1 (mixture of levonorgestrel and quinestrol) on male greater long-tailed hamsters (Tscherskia triton). Hamsters in the treatment group were provided with wheat baits with 0.001% EP-1 for six consecutive days, while hamsters in the control group were provided with plain wheat. One week and three weeks later, reproductive organs of hamsters of both groups were measured, respectively. We found the size or weight of testis, spermatophore and epididymis of the treatment group were significantly reduced compared to those of the control group, and this reduction was greater in the third week compared to that of the first week. The results indicate that EP-1 is able to reduce the fertility of both male and female hamsters.更多还原