Objective To study the effect of cordyceps culture medium additive on growth and reproductive performance of Wistar rats. Methods To collect and analyze the growth and reproductive performance data of 51 male and 150 female Wistar rats, and to take ovary and testis samples to make pathological examination. Results The growth of Wistar rats became slower, the availability of feedstuff in male rats was slightly increased, and the mating rate of rats and rats/litter were not significantly different from that of control group. No essential lesions occurred in the ovary and testes after feeding cordyceps culture medium additive. Conclusion Cordyceps culture medium additive had no specific effect on growth and reproductive performance of Wistar rats.