Probiotics After Rifaximin May Reduce Relapse in IBS-D: JGH | August 2026

Introduction:

Rifaximin can improve symptoms in diarrhoea-predominant irritable bowel syndrome (IBS-D), but relapse after treatment remains common. Because rifaximin alters the intestinal microbial environment, post-treatment microbiome modulation may help sustain response. This multicenter randomised trial evaluated whether a 4-week probiotic consolidation course after successful rifaximin therapy could reduce IBS-D recurrence.

Why was this study needed?

Many rifaximin-responsive patients subsequently relapse.

Strategies to maintain remission after rifaximin are poorly established.

Probiotics could potentially stabilise post-rifaximin microbiome changes.

The study also explored microbial signatures associated with recurrence.

Results:

143 rifaximin responders were randomised to 4 weeks of Bacillus subtilis + Enterococcus faecium (Medilac-S) or no further treatment.

Relapse was significantly lower with probiotic consolidation: 40.0% vs 58.3%.

Probiotic-treated patients also had fewer bowel movements and better stool consistency.

Relapse was associated with distinct microbiome patterns, including increased Faecalibacterium and Streptococcus abundance.

Clinical Impact:

The study introduces an interesting induction–consolidation strategy for IBS-D: rifaximin to achieve initial response followed by targeted probiotic therapy to help maintain it. The absolute reduction in relapse was about 18%, corresponding to roughly 6 patients treated to prevent one relapse.

However, this was a relatively small, open-label trial, and the probiotic findings are formulation-specific. Larger blinded studies are needed before routine probiotic consolidation after rifaximin can be recommended.

Bottom Line:

In rifaximin-responsive IBS-D, 4 weeks of probiotic consolidation reduced subsequent relapse from 58% to 40% and improved stool frequency and consistency. The concept of microbiome-directed maintenance after rifaximin is promising—but requires independent validation before becoming standard practice.