Bifidobacterium longum is a probiotic bacterium that has been investigated for its potential in supporting gastrointestinal health, including inflammatory bowel diseases such as Crohn's Disease (CD). The rationale for its use is based on the understanding that dysbiosis (an imbalance in the gut microbiota) plays a role in the pathogenesis of CD. B. longum is thought to help restore microbial balance, modulate the immune response, and reinforce the intestinal barrier.

While there is a scientific basis for considering probiotics in CD, the level of evidence specifically for B. longum is limited and not definitive. Several small-scale clinical studies and animal models suggest that certain strains of B. longum (such as B. longum 35624) may reduce inflammation and support mucosal healing. For example, a few randomized controlled trials have demonstrated modest improvement in symptoms and inflammatory markers in patients with inflammatory bowel disease (IBD) using probiotic combinations that include B. longum. However, these studies often involve mixed probiotic formulas and small sample sizes, making it difficult to attribute benefits to B. longum alone or to generalize the results to all CD patients.

Major gastroenterology guidelines currently do not recommend probiotics as standard therapy for Crohn’s Disease due to insufficient high-quality evidence. Therefore, while there is some scientific support, it is not strong, and further large-scale, well-controlled studies are needed.