A AB BS S T TR RA AC CT T O Ob bj je ec ct ti iv ve e: : This study proposed to investigate whether magnesium sulfate (MgSO 4 ) could reduce the ovarian damage induced by cyclophosphamide (Cyc). M Ma at te er ri ia al l a an nd d M Me et th ho od ds s: : Thirty female rats were used for this study: Control group (n=10)-Only laparotomy; Cyc group n=10)-75 mg/kg Cyc intraperitoneally; and Cyc+MgSO 4 group (n=10)-75 mg/kg Cyc on day 0 and 200 mg/kg MgSO 4 on days 1-7 (both intraperitoneally). The extent of histopathological damage and the number of ovarian follicles were determined. The levels of anti-Mullerian hormone (AMH) were measured in blood samples. R Re es su ul lt ts s: : Statistically significant differences in the AMH values were observed in the control group versus Cyc group and Cyc group versus Cyc+MgSO 4 group (p<0.05). The levels of AMH were the least in the Cyc group. The total tissue damage in the Cyc group was significantly higher than that in the control, as well as in the Cyc+MgSO 4 group (p<0.05). The follicle counts were the least in the Cyc group. C Co on nc cl lu us si io on n: : Cyc caused ovarian damage and reduced the ovarian reserves. The ovarian reserves in the MgSO 4 -treated group were better than those in the other groups, and there was least ovarian damage in the MgSO 4 -treated group.K Ke ey yw wo or rd ds s: : Cyclophosphamide; anti-Mullerian hormone; magnesium sulfate