Efficacy and safety of fecal microbiota transplantation in Parkinson's disease: a systematic review and meta-analysis of randomized controlled trials with GRADE assessment.

BACKGROUND

Parkinson's disease (PD) is a common neurodegenerative disease that is a growing public health challenge. Recent evidence showed that gut microbiota dysbiosis is involved in the pathogenesis of PD, prompting interest in fecal microbiota transplantation (FMT) as a potential disease-modifying intervention. This systematic review and meta-analysis aim to evaluate the efficacy and safety of FMT in patients with PD.

METHODS

We conducted a systematic literature review using PubMed, Scopus, Web of Science, and the Cochrane Library till June 4, 2026, to identify RCTs comparing FMT with placebo or control interventions in PD. After removal of duplicates alongside title and abstract screening, followed by full-text screening, seven randomized controlled trials were included in this systematic review and meta-analysis.

RESULTS

A total of seven randomized controlled trials (RCTs) with 318 subjects were analyzed. FMT was delivered via oral capsules, nasojejunal tubes, or colonoscopy, with follow-up periods ranging from 12 to 52 weeks. The meta-analysis indicated a notable short-term enhancement in daily motor activities, as assessed by MDSUPDRS Part II, after one month (mean difference - 2.19, 95% confidence interval - 4.32 to -0.06; P = 0.044). Nevertheless, no significant estimates were noted for MDS-UPDRS Part III, aggregate MDS-UPDRS scores, motor complications, non-motor symptoms, or overall life quality at any assessed time frame. Some individual studies reported gains in cognitive ability, anxious feelings, quality of life related to constipation, and certain PDQ-39 categories, although these improvements were not uniformly observed. Overall, FMT was well tolerated by participants, with adverse reactions mostly comprising mild, self-resolving gastrointestinal issues and no major safety risks.

CONCLUSIONS

FMT is a safe treatment for individuals with PD and may offer modest short-term advantages in performing daily motor tasks. However, current evidence does not indicate lasting enhancements in overall motor capabilities, non-motor symptoms, or life quality. More extensive and sufficiently powered trials utilizing standardized FMT procedures and longer observation periods are necessary to elucidate the therapeutic benefits of FMT in Parkinson's disease.