Background:The purpose of this study was to investigate the efficacy and safety of Jollab monzej (JMZ), a Traditional Persian compound medicine, on multiple sclerosis-related fatigue (MSRF).Methods:We did a double-blind randomized controlled phase3 clinical trial on the JMZ syrup in fifty-six relapsing-remitting MS (RRMS) patients aged 18-55 years with moderate to severe fatigue using the Expanded Disability Status Scale (EDSS) score ≤ 6. We randomly assigned (1;1) participants to the JMZ syrup or placebosyrupgroups treated for one month. Participants, investigators, and assessors were unaware of the assignments. The primary outcome was changes in the fatigue score on the Fatigue Severity Scale (FSS), at baseline and one month after treatment using the intention-to-treat (ITT) analysis. The secondary outcomes were changes in the score of Visual Analogue Scale (VAS), Beck Depression Inventory (BDI), and Pittsburgh Sleep Quality Index (PSQI). Outcomes were measured at baseline, one month after treatment, and 2-week follow-up. Safety was detected in all participants.Results:We randomly assigned 56 participants to the JMZ group (n=28) and placebo group (n=28). Fatigue scores significantly changed in both groups; however, the JMZ group had a greater reduction in FSS score in the ITT analysis. The adjusted mean difference was 8.80 (Confidence interval (CI) 95%, 2.90-14.70, P = 0.00). The mean difference of VAS, BDI, and global PSQI scores were statistically significant (P=0.01, P₌0.00, P₌0.01; respectively). Regarding safety, mild adverse events (AEs) were reported.Conclusion:The results of our study revealed that the administration of JMZ syrup alleviated MSRF and also could improve depression and sleep disorders.