Abstract / Summary
Objective: Fecal microbiota transplantation (FMT) has emerged as a potential therapeutic approach targeting the gutbrain axis in Parkinson's disease (PD).This study aimed to address these gaps.Methods: A systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted using Medline, Scopus, Cochrane Library, and ClinicalTrials.gov up to May 5th, 2026.Outcomes were synthesized as mean differences or odds ratios using a random-effects model.Results: Seven RCTs were included.FMT demonstrated greater short-term improvement in overall disease severity, with significant reductions in total MDS-UPDRS scores at 1 and 3 months, but no sustained benefit at later follow-up.Improvements in non-motor symptoms (MDS-UPDRS Part I) were observed at intermediate time points, whereas motor function (Part III) showed no significant differences across all time points.Quality of life (PDQ-39) and non-motor symptom burden (NMSS) improved at early follow-up but were not consistently maintained.FMT significantly enhanced bowel function, including increased complete spontaneous bowel movements and improved stool consistency during the first three months.Cognitive outcomes showed no meaningful improvement based on MoCA and MMSE.No significant effect on levodopa equivalent daily dose was identified.FMT was associated with a higher incidence of overall and gastrointestinal adverse events, although these were generally mild and transient.Conclusion: Current evidence suggests that FMT may be associated with limited, time-dependent improvements in selected non-motor symptoms and bowel function in PD, while effects on motor and cognitive outcomes remain uncertain; reported adverse events were mostly mild, although short-term safety concerns warrant consideration.