Background: Chemotherapeutic agents are associated with different unwanted effects; the dangerous are mutagenic actions. Researchers do their best to ameliorate such effects by different supportive agents.  
Objective: The study designed to demonstrate the mutagenicity of the chemotherapeutic drugs especially cyclophosphamide [CP] and possible protective effects of Zinc Chloride [Zn Cl]
Materials and Methods: The experiment was designed as 4 groups each group contain 12 animals, the first group [control group] was injected intraperitoneal normal saline [1 ml/kg] every other day for 20 days, the second group was given intraperitoneal Zn Cl [4 mg/kg] every other day for 20 days. The third group [Test group] injected by intraperitoneal cyclophosphamide [200 mg/kg] as a single dose on 15^th day of experiment, Fourth group [protective group] was given intraperitoneal ZnCl  [4 mg/kg] every other day for 20 days and injected intraperitoneal single dose by CP  [200 mg/kg] on 15^th day.
Results: There were significant changes in blood cells, mitotic index and increased frequency of structural and numerical changes in chromosomes compared with the control group and these outcomes attributed to effects of free radicals of CP on health cells. The protective effect of Zn Cl which decrease blood cell changes, the structural and numerical aberrations in relation to the test group. 
Conclusion: CP has harmful effects on the blood cells and chromosomes. Zinc Chloride has a protective effect against the harmful effects of CP.