Lactococcus lactis is a lactic acid bacterium traditionally used in dairy fermentation, but its role as a probiotic for Inflammatory Bowel Disorders (IBD), such as Crohn's disease and ulcerative colitis, has also been explored. The scientific basis for its use is primarily from preclinical studies and limited clinical data. Animal models of colitis have shown that certain strains of L. lactis can reduce inflammation, modulate immune responses, and improve gut barrier function. These effects are thought to be mediated by the production of anti-inflammatory cytokines and enhancement of mucosal healing. For example, recombinant L. lactis strains engineered to deliver anti-inflammatory molecules such as interleukin-10 (IL-10) have demonstrated efficacy in reducing colitis severity in mice.

However, direct evidence in humans remains sparse. A few small-scale clinical trials have indicated potential benefits, but results are inconsistent and often strain-specific. Most clinical recommendations for probiotics in IBD focus on other genera, such as Lactobacillus or Bifidobacterium. As a result, while there is a scientific rationale and some promising preclinical data for L. lactis, robust clinical evidence supporting its efficacy for IBD is currently limited. Its use is not based on longstanding traditional practice for IBD, but rather on recent scientific investigations.