Top Probiotics for Treatment of IBS
The American Gastroenterological Association makes no recommendation for probiotics in IBS due to low-quality evidence, and suggests using them only in clinical trials—however, if you choose to trial probiotics despite this guidance, an 8-strain combination or specific single strains like Bifidobacterium bifidum MIMBb75 or Bacillus coagulans MTCC 5856 show the most promise for symptom reduction. 1
The Evidence Landscape
The fundamental problem with probiotics in IBS is that 44 different probiotic species, strains, or combinations have been tested, with most evidence coming from single trials with small sample sizes and very low certainty of evidence. 2 The overall certainty of evidence across all critical outcomes for probiotics in IBS is Low to Very Low. 2, 1
Why Guidelines Don't Recommend Probiotics
- The AGA specifically recommends against routine probiotic use for IBS symptoms because of significant heterogeneity in study designs, inconsistent outcomes, and lack of reproducibility across trials. 1
- Treatment with probiotics is not recommended for bloating or distention according to AGA guidelines. 1
- The mechanisms by which probiotics might work in IBS remain largely unknown, making strain selection empiric rather than evidence-based. 2
If You Still Choose to Trial Probiotics
Multi-Strain Combinations (Strongest Evidence)
An 8-strain combination may decrease abdominal pain (mean decrease -3.78; 95% CI -4.93 to -2.62), though with very low certainty of evidence: 2, 1
- Lactobacillus paracasei subsp. paracasei
- L. plantarum
- L. acidophilus
- L. delbrueckii subsp. bulgaricus
- Bifidobacterium longum subsp. longum
- B. breve
- B. longum subsp. infantis
- Streptococcus salivarius subsp. thermophilus
This combination showed benefit in two trials for abdominal pain in adults, with small sample sizes and unclear risk of bias. 2 For children with IBS, this same 8-strain combination may improve abdominal pain scores. 2
Single-Strain Probiotics with Supporting Evidence
For overall IBS symptom improvement (based on single trials with low-quality evidence): 2
- Bifidobacterium bifidum MIMBb75 showed benefit for global IBS symptoms and ranked highly in network meta-analysis (4 × 10⁹ CFU/day for 4 weeks). 2, 3
- Lactobacillus plantarum 299v improved both global symptoms and abdominal pain in single trials. 2
- Bacillus coagulans MTCC 5856 improved abdominal pain scores and ranked first for Bristol stool form improvement in IBS-D (SUCRA 99.6%). 2, 4
For IBS with diarrhea specifically:
- Clostridium butyricum CBM588 showed >80% reduction in diarrhea episodes and ~60% reduction in stool frequency in a 2025 open-label study of 205 patients, with increased gut microbiota diversity. 5
- Saccharomyces cerevisiae CNCM I-3856 ranked highly (SUCRA 89.7%) for improving Bristol stool form in IBS-D. 4
What Does NOT Work
Saccharomyces boulardii showed no benefit for IBS abdominal pain in three studies involving 232 adults (standardized MD 0.26; 95% CI -0.09 to 0.61). 2, 1, 6 Despite being effective for C. difficile prevention, it has no role in IBS treatment. 6, 7
Practical Clinical Algorithm
Step 1: Prioritize Evidence-Based First-Line Treatments
- Soluble fiber (psyllium) 3-4 g/day initially, gradually increasing to avoid bloating. 1
- Regular exercise for all IBS patients. 1
- Low FODMAP diet as second-line dietary therapy for global symptoms and abdominal pain. 1
Step 2: If Considering Probiotics Despite Guideline Recommendations
- Discuss with patients that probiotics are not guideline-recommended and evidence quality is very low. 1
- For adults with predominant abdominal pain: Trial the 8-strain combination listed above for 4-8 weeks. 2, 1
- For IBS-D specifically: Consider Bacillus coagulans MTCC 5856 or Clostridium butyricum CBM588. 5, 4
- For general symptom improvement: Consider Bifidobacterium bifidum MIMBb75 at 1 × 10⁹ CFU/day for 4 weeks. 3
Step 3: Monitor and Adjust
- Stop probiotics immediately if symptoms worsen, particularly bloating, as some patients experience increased fermentation-related symptoms. 1, 5
- Reassess after 4-8 weeks—if no improvement, discontinue as continued use is not supported by evidence. 2
Critical Pitfalls to Avoid
- Do not recommend probiotics based on manufacturer claims without supporting published evidence. 1
- Avoid probiotics in immunocompromised patients due to risk of fungemia or systemic infection, particularly with S. boulardii. 7
- Do not use probiotics as primary treatment when other evidence-based approaches are available. 1
- Recognize that most positive studies are single trials that lack confirmation—publication bias is substantial in this literature. 2
- Evaluate for underlying causes (SIBO, carbohydrate intolerances, celiac disease) before attributing symptoms solely to IBS. 1
The Bottom Line on Quality of Evidence
Meta-analyses show no significant benefit when single-strain probiotics are grouped at the genus level, though some meta-analyses suggest potential benefit from multi-strain combinations. 2 Network meta-analysis identified Lactobacillus acidophilus DDS-1 ranking first for IBS Symptom Severity Scale improvement (SUCRA 92.9%), but this is based on limited data. 4 The reality is that most probiotics showing benefit in IBS have only been studied once, with small sample sizes, variable quality, and high risk of bias. 2