Bifidobacterium species, particularly in mixed probiotic formulations, have garnered scientific interest for their potential role in supporting or treating colitis, especially ulcerative colitis (UC). Several randomized controlled trials and meta-analyses have evaluated their efficacy, often in combination with other probiotic strains like Lactobacillus. The most well-known combination is VSL#3, a high-potency probiotic mixture containing multiple strains including several Bifidobacterium species.

Studies suggest that mixed probiotics can help induce and maintain remission in mild to moderate ulcerative colitis. The proposed mechanisms include modulation of the gut microbiota, enhancement of mucosal barrier function, and reduction of inflammatory cytokines. A 2020 Cochrane review concluded that probiotics may be more effective than placebo for maintaining remission in UC, though the quality of evidence is moderate and most benefit is seen with multi-strain products. Evidence for Crohn's disease and microscopic colitis is less robust and more equivocal.

In summary, scientific evidence—though not unequivocal—supports the use of Bifidobacterium-containing probiotic mixtures as adjunctive therapy in ulcerative colitis. However, probiotics should not replace standard medical treatments, and not all patients will respond. The evidence base is growing but remains moderate in strength, justifying a score of 3 out of 5.