Lactococcus rhamnosus (often referred to in the literature as Lactobacillus rhamnosus, especially the GG strain, LGG) is a probiotic bacterium that has been studied for its potential role in supporting or treating Irritable Bowel Syndrome (IBS). Several clinical trials and meta-analyses have evaluated the efficacy of L. rhamnosus in improving IBS symptoms such as abdominal pain, bloating, and stool irregularity. While some studies suggest modest benefits, the overall quality and consistency of evidence are moderate at best.

For example, a 2014 systematic review (Didari et al., World J Gastroenterol) found that certain probiotic strains, including L. rhamnosus GG, may offer some improvement in global IBS symptoms, though effects are often strain-specific and not universally observed. More recent reviews (Ford et al., 2018, Am J Gastroenterol) note that while probiotics as a group may be beneficial, the evidence for L. rhamnosus specifically remains limited and results from individual studies are mixed.

The mechanism by which L. rhamnosus could help with IBS is thought to involve modulation of the gut microbiota, enhancement of intestinal barrier function, and immunomodulatory effects. However, due to heterogeneity in patient populations, IBS subtypes, probiotic strains, and study designs, clinical guidelines generally consider the evidence as low to moderate quality.

In summary, there is some scientific validation for the use of L. rhamnosus in IBS, but evidence is inconsistent and not strong enough for unequivocal recommendations. The use is not rooted in tradition but rather in modern clinical research.