Abstract: The serum concentrations of testosterone, LH and FSH in healthy men and in men taking gossypol were determined by radioimmunoassy. Gossypol acetic acid was given orally at a daily dose of 15 mg until infertility appeared, followed by 15 mg on alternate days for 1～79 months. 141 cases were divided intoa control group of 66 cases anda medication group of 75 cases. The medication group was subdivided into 6 sub-groups, according to the various durations of medication. control Results indicated that the serum concentration of testosterone, LH and FSH in the group were 18.6±7.6 nmol/1,9.1±5.2 IU/1 and 7.2±4.1 IU/1 respectively. The serum testosterone and FSH levels in the medication groups, with the exception of the first group (12 months), were significantly higher than that of the control group (p<0.01). There were no significant difference between values of serum LH in all Qf the medicated groups and control group (p>0.05). The higher FSH and testosterone levels indicated severe damage of the germinal epithelium without obvious damage of the Leydigs cells in men taken gossypol acetate.