Artemisinin-based therapies remain the primary treatment for malaria; however, the concurrent use of antioxidant supplements during therapy is common in endemic regions. Emerging evidence suggests that antioxidants such as ascorbic acid (AA) may interfere with the antimalarial efficacy of dihydroartemisinin (DHA). The present study investigates the dose- and timing-dependent interaction between AA and DHA using a \textit{Plasmodium berghei}-infected murine model. Multiple AA dosing regimens and administration schedules were evaluated to assess parasite clearance, oxidative stress, and hepatic injury markers. The results demonstrate that high-dose and simultaneous AA administration significantly attenuates DHA-mediated parasite clearance, whereas delayed AA administration preserves antimalarial efficacy while partially modulating hepatic oxidative stress. These findings highlight the importance of dosing strategy and timing in minimizing adverse drug–nutrient interactions and support the development of evidence-based guidelines for antioxidant supplementation during malaria therapy.
