FMT in IBS: Gastroenterology | July 2026

Introduction:

Gut microbiota alterations have been implicated in the pathogenesis of irritable bowel syndrome (IBS), making fecal microbiota transplantation (FMT) a promising therapeutic strategy. However, clinical trials have reported conflicting results. This updated meta-analysis evaluated the efficacy and safety of FMT in patients with IBS.

Why was this study needed?

• Previous FMT trials in IBS have reported inconsistent outcomes.
• The role of gut microbiota modulation in IBS remains uncertain.
• Larger pooled analyses are needed to clarify the true efficacy of FMT.
• Variability in donor selection, FMT protocols, and patient populations has limited interpretation.
• Clear evidence is required before recommending FMT in routine IBS practice.

Results:

• FMT did not significantly improve IBS symptoms compared with placebo in the primary intention-to-treat analysis.
• Although some patients who completed treatment appeared to benefit, the overall quality of evidence was very low, with substantial variation across studies.
• FMT was generally safe, with adverse events comparable to placebo, but current evidence does not support its routine use for IBS.

Clinical Impact:

This comprehensive meta-analysis suggests that FMT should not be routinely offered for IBS outside clinical trials. Future research should focus on identifying the patients most likely to benefit and standardizing donor selection, stool preparation, and treatment protocols.

Bottom Line:

Current evidence does not demonstrate a clear clinical benefit of FMT for IBS. While the procedure appears safe, its routine use cannot be recommended until higher-quality, standardized clinical trials identify the appropriate patients and optimal treatment strategies.