This study was designed to investigate the myeloprotective activity of methanolic leaf extract of Jatropha tanjorensis in cyclophosphamide induced bone marrow suppression in albino wistar rats. Myelosuppression was achieved by intraperitoneal injection of 3mg/kg of cyclophosphamide for 7 consecutive days. The extract was tested orally at 200 mg/kg and 400 mg/kg, given for 14 days, while Vitamin B complex (a hematinic) served as a reference drug. The degree of protection was determined by measuring the levels of hematological parameters such as: TWBC, RBC, PCV, HB and Reticulocyte count. Results obtained showed that both doses of the extract significantly (p < 0.05) increased the values of all the hematological indices estimated, which included: total white blood cells, red blood cells, packed cell volume, hemoglobin and reticulocyte count. The activity of the extract was dose – dependent and comparable to that of that reference drug. The results thus suggest that Jatropha tanjorensis may possess myeloprotective activity when administered orally in cyclophosphamide induced bone marrow suppression. This finding supports the folkloric use of the leaves of this plant for prevention and treatment of anaemia
