Introduction: Lung cancer is an important burden, causing a massive rate of deaths every year. Using a specialized treatment regimen can improve treatment outcomes and reduce treatment-related adverse events. This study aimed to evaluate the protective effects of the Opuntia dillenii fruit hydroalcoholic extract (ODHAE) in a mouse model of lung cancer. Methods: Eight groups of lung cancer-induced BALB/c mice (each containing twelve animals) were included in this study. They were the control group, groups receiving the ODHAE extract at doses of 50, 100, and 200 mg/kg by oral gavage, the cisplatin group receiving cisplatin intraperitoneal injection, and groups receiving cisplatin and different doses of ODHAE (50, 100, and 200 mg/kg). Weight and tumor changes were evaluated in the short and long phases of the study, including 30 and 90 days, respectively. Liver transaminase and survival time were evaluated in different groups. Malondialdehyde (MDA) was evaluated in different groups as an indicator of lipid peroxidation. Statistical tests were performed using GraphPad Prism 8. Graphs were designed using GraphPad Prism 8 as well. Results: The observed weight changes were not statistically significant across all groups, except for group 8. However, in groups that did not receive cisplatin treatment, there was a significant increase in tumor volume. Conversely, tumor volume change did not reach statistical significance in all groups receiving cisplatin. The administration of ODHAE, along with cisplatin, demonstrated a dose-dependent increase in the survival time among the relevant groups. Furthermore, oral administration of ODHAE exhibited a significant reduction in transaminase levels, serving as a reliable biomarker for assessing the hepatoprotective effect of the ODHAE extract. Additionally, ODHAE displayed a dose-dependent reduction in MDA levels, indicating its potential as a therapeutic agent for mitigating oxidative stress. Conclusion: The administration of ODHAE was not effective in reducing tumor growth but significantly increased survival time and healed the liver injury induced by cisplatin.