Background: The unusual accelerated division of group of cells is known as tumor, which may spread out through the body causing what is known as cancer. Quercetin is a well-known flavonoid which is abundant in many plants, and thought to have many therapeutic effects. Aim of the study: The study performed to evaluate the anti-tumor potential of Quercetin against solid Ehrlich tumor in female mice. Method: The study was carried out on 5 groups of female mice; Group I (Negative control), group II (Ehrlich tumor only), group III (Ehrlich+Methotrexate), group IV (Ehrlich+Quercetin) and group V (Ehrlich+Methotrexate +Quercetin). Estimation of Quinone Reductase and Aromatase enzymes activities, Malondialdehyde(MDA) concentration, Tumor Volume, percentage of DNA damage and Survivability were detected, in addition to genomic instability via RAPD-PCR. Results: Under the influence of Quercetin administration to the tumor bearing mice; Quinone Reductase was increased, Aromatase was decreased, MDA was decreased, DNA damage was lowered, and Tumor volume was shrinked, RAPD-PCR showed the nearest pattern of bands to control and survivability was prolonged. Conclusion: The results proved an anti-tumor potential of Quercetin with a suggestion of co-administration of Quercetin together with Methotrexate as the best choice for cancer treatment.