Abstract: In a large number of epidemiological studies investigating relationship between diet and cancer, a protective effect of the consumption of vegetables and fruits on various types of cancer has been found. This protective effect has been generally attributed to the antioxidative capacities of the constituents present in these foods. The search for natural agents that protect against tumorigenesis is important to those at risk by virtue of environmental pollution or health-related treatment as well as for scientific study of the mechanism of the potential therapeutic application of these agents. The present research is a trial to evaluate the chemopreventive effect of oral administration of oil extracted from the leaves of Coriandrum sativum (1 mg/kg) in mice inoculated with Ehrlich Ascites Carcinoma with or without exposure to fractionated doses of gamma irradiation (up to 6 Gy). Significant increase in malondialdehye (MDA) level accompanied with significant decrease in catalase activity in both liver and tumor tissue in the group of mice, bearing tumor while total protein content was increased in tumor tissue. Serum iron was inversely proportional to the level of transferrin and total iron binding capacity (TIBC) levels. Application of coriander oil to mice bearing tumor caused partial amelioration in the assayed parameters. Such amelioration was pronounced in restoring the level of MDA in liver to the control level while, tumor tissue still suffered from sharp increase in MDA content. Combined treatment of coriander oil followed by irradiation exerted a protective effect on the elevation of MDA content induced by tumor growth in both liver and tumor tissue. Successful application of coriander oil in radiotherapeutic practices still awaits further investigation on the optimal to be used in clinical trial and whether or not it will be with value when used with fractionated radiotherapy.