Background & aim: Cyclophosphamide is an anti cancer drug which causes alkylation of DNA in cells. The side effects of cyclophosphamide are bone marrow damages and anemia. Hypericum perforatum is a medicinal plant which widely used in traditional medicine. In this study the hemotopoetic effect of Hypericum perforatum leaf extract (HPE) on bone marrow function and blood parameters in male rat were treated with cyclophosphamide was investigated.

Methods: Forty two male Wistar rats with an average body weight of 220±25 gr were randomly divided into 6 groups (n=7): control group taking normal saline,0.5ml/day, i,p ),witness group taking cyclophosphamide (15mg/kg/day, i.p.), positive control group taking HPE (200mg/kg, i.p/day),  treated groups 1, 2 and 3 recieved cyclophosphamide ,(15mg/kg/day, i.p. + 100mg/Kg, 200mg/Kg and 400mg/kg  HPE /day for 10 days, i,p). At the end of study blood samples were collected from heart directly. RBC, WBC, Hct, Hb and PL were meseaured. Data are presented as mean ± standard deviation and were analyzed using ANOVA and Tukey tests.

Results: The results indicated that cyclophosphamide caused damage on bone marrow, which in this case significantly reduced the number of blood cells and platelets in the group treated with cyclophosphamide (P<0.001). Blood parameters in the groups treated with HPE increased significantly compared with the group which received cyclophosphamide alone (P<0.001).

Conclusion: The Hypericum perforatum hydoethanolic extract contains antioxidant and flavonoids compounds which could protect the bone marrow tissues against cyclophosphamide.