This paper focused on how to successfully carry out nonclinical reproductive toxicity study on drugs.The following issues are principally argued.① In the rat fertility and early embryonic development toxicity test(I section),sexually mature young adult animals and nulliparous female animals should be selected.Male drug administration period more than nine weeks is more reliable before mated.The use of hospital human sperm quality analysis system is not recommended;manual microscopy or animal sperm analysis ...