This systematic review and meta- analysis aims to assess the safety and efficacy of fecal microbiota transplantation as an innovative treatment to improve symptoms in PD patients.

A comprehensive literature search was conducted across PubMed, Cochrane, Embase  and clinicaltrials.gov from inception until March 2025 to identify relevant studies. Risk ratios (RR) for dichotomous outcomes and mean differences (MD) for continuous outcomes with 95% confidence intervals (CI) were calculated using a random-effects model. Statistical heterogeneity was assessed using the I² and X² statistics and the statistical calculations was performed using RevMan 5.4.1. A p-value of <0.05 was considered statistically significant.

This meta-analysis included 4 studies involving 159 patients with a mean age of  63.36 ±2.92 years. We found out significant improvement  were observed in quality of life (PDQ-39/PDQOL) (MD 5.92; 95% CI: 2.17 to 9.68; P=0.002; I²=0%), Geriatric depression scale (MD -1.22; 95% CI: -2.28 to - 0.17; P=0.002; I²=0%), and Wexner constipation score (MD 1.95; 95% CI: 0.67 to 3.22; P=0.003; I²=0%). FMT did not significantly improve cognitive function as assessed by Montreal Cognitive Assessment (MoCA), non-motor symptoms (NMSS), Parkinson Anxiety Scale and MDS-UPDRS scores (I–IV). Adverse events including nausea, flatulence, bloating and diarrhea were similar between FMT and placebo groups.

We found that FMT may offer improvements in quality of life, depression, and constipation symptoms in patients with Parkinson’s disease. Small sample sizes and heterogeneity in some outcomes may limit our findings. Robust studies with larger sample size are required to establish conclusive evidence.