Background : Cetirizine is an antihistaminic drug and inhibits nitric oxide production which itself inhibits steroidogenesis. The present study was conducted to evaluate the effect of cetirizine on the concentration of steroidal hormones testosterone, FSH and LH and spermatogenesis.

Materials and Methods: Fifty adult male Wistar rats were divided into five groups of ten. All the groups were kept under daily dark and light cycle conditions. These groups included control group (receiving water and food), sham group (receiving distilled water as drug solvent) and three experimental groups (receiving 20, 40, 80 mg/kg/B.W of cetirizine orally). After 28 days, blood samples were taken from the rats to measure the serum concentrations of testosterone, FSH, and LH hormones using RIA method. In addition, tissue sections of the rats' testes were stained to find out histological changes during the experiment. Statistical analysis of the data was carried out using ANOVA and DUNCAN tests.

Results : The results obtained from this study indicated that the concentration of testosterone in the blood of the experimental rats increased relatively (p ≤ 0.05), but no significant changes have been observed in the concentrations of LH and FSH hormones during the experiment.

Conclusion: It can be concluded that cetirizine probably increases the concentration of testosterone due to increasing LH receptor in leydig cells. On the other hand, the results obtained from the histological studies showed that cetirizine has affected neither sertoli nor leydig cells and spermatogenesis.