Background: Glioblastoma (GBM) is the most common primary central nervous systemmalignancy with a low survival without extra logistics. Currently, there is no definitivechemotherapy among the studied options. This study aims to evaluate the neuroprotectiveeffects of dimethyl fumarate (DMF) on surgical brain injuries in patients treated for GBM.Materials and Methods: This randomized, phase II, placebo, triple-blinded, controlled trialwas performed on 36 patients with a diagnosis of GBM. All the patients received DMF (240mg, three-times per day) or placebo (with the same shape and administration route) one weekbefore surgery. Also, patients in both groups after the operation received standard treatments(radiotherapy plus chemotherapy). In addition, Kanofsky's performance status (KPS) score wasevaluated at baseline and one month later. Also, serum S100β was measured 48 hours beforeand after surgery. Results: There was no significant difference among DMF and control groupswith regard to age, gender, and the extent of resections (P˃0.05). The most adverse event inboth groups was a headache. Although the serum S100β level was not markedly changed aftersurgery, the mean KPS in the DMF group was higher than in the control group after surgery.Conclusion: The DMF could be a possible good regime for the treatment of GBM; however,questions are raised regarding its efficacy and application for the addition to standard treatment.[GMJ.2022;11:e1897]