Vegetables and its by-products become and still play an important role in human nutrition and health, they are rich in phytonutriceuticals as vitamins, minerals, dietary fiber, phytochemicals and antioxidants. So, this work was carried out to study the effect of feeding tumored mice on 5% turnip (Brassica rapa var.rapa L) leaves powder on tumor cell volume, cell viability, oxidative stress, antioxidants enzymes activities and functions of liver and kidney in female Swiss Albino mice. The results showed that the turnip leaves powder had high nutritional value; which it is rich in minerals, fiber, phenolic and flavonoid compounds. Moreover, as a result of feeding tumored female mice on turnip leaves powder 5% caused a significant (p≤0.05) decrease in volume and count (cell viability) of tumor cell for both preventive and therapeutic groups compared to the positive control group. Meanwhile, the therapeutic group revealed the highest percentage of inhibitory for tumor cell. Moreover, the results indicated that the levels of MDA were significantly decreased and levels of SOD and CAT were significantly (p≤0.05) increased for both preventive and therapeutic groups compared to the positive control group in liver tissues homogenate. Furthermore, liver enzymes and kidney function as urea nitrogen and creatinine of tumored female mice were decreased as a result of feeding on turnip leaves powder. So, the therapeutic group feeding on 5% turnip leaves had the lowest levels of all these analyses compared to the positive control group. Finally, turnip leaves powder and its ethanolic extract had antitumor activity against MCF-7 cells ( human breast cancer cell line) in vitro and Ehrlich ascites carcinoma (EAC) in vivo. Also, it enhance the antioxidants enzymes activities in addition, turnip leaves powder caused improvement in liver and kidney function in female Swiss albino mice. So, it can be used in preparing traditional foods for prevention and supplementation foods for cancer patient during therapeutic period.