Pediococcus acidilactici is a probiotic lactic acid bacterium that has been investigated for potential benefits in gastrointestinal health, including Irritable Bowel Syndrome (IBS). The scientific evidence supporting its use for IBS is limited but emerging. Some small clinical studies and animal models suggest that P. acidilactici may help modulate the gut microbiota, improve intestinal barrier function, and reduce inflammation, all of which are relevant to IBS pathology. For example, a few randomized controlled trials using multi-strain probiotic supplements containing P. acidilactici (often in combination with Bacillus subtilis) have reported improvements in symptoms such as abdominal pain, bloating, and stool irregularity in IBS patients. However, most of these studies are small, use mixed probiotic formulations (making it difficult to isolate the effect of P. acidilactici), and are sometimes sponsored by industry.

Systematic reviews of probiotics in IBS generally focus on more commonly studied strains (like Lactobacillus or Bifidobacterium), and only mention P. acidilactici incidentally. There is currently insufficient high-quality, large-scale, independent research to firmly establish its efficacy for IBS. Thus, while there is some early scientific support and plausible mechanisms, the overall level of evidence is modest (rated 2/5).