Leukemia is a broad term covering a spectrum of diseases. It is a part of the even broader group of diseases called hematological neoplasm. This study was undertaken to clarify the hematological and biochemical changes accompanied with leukemia induced experimentally in rats with benzene administration and its treatment using certain anticancer drugs such as Methotrexate and Doxorubicin. The biochemical parameters were widely investigated. The obtained results illustrated that some chemicals have a toxic effect on blood cells, bone marrow and body organs. such as liver, kidney and heart. Uses of anticancer drugs such as Methotrexate and Aldoxeirobsin in the treatment of blood cancer lead to liver toxicity and adverse effect on heart and increased rates of kidney functions, increase in some types of fat, lower rates for other natural and a lack of hemoglobin and increased oxidation of fat. Therefore we recommend avoiding toxic chemicals, especially benzene as possible and the work of analysis to complete blood sugar and liver function, kidney and fat and cardiac enzymes and analysis of the thyroid on a regular basis for patients with leukemia and cancer.