Bifidobacterium species are commonly used as probiotics to help prevent or alleviate the gastrointestinal side effects associated with antibiotic use, particularly antibiotic-associated diarrhea (AAD). The scientific rationale is that antibiotics disrupt the natural balance of gut microbiota, often reducing populations of beneficial bacteria like Bifidobacterium, which can lead to overgrowth of opportunistic pathogens such as Clostridioides difficile or other harmful bacteria. Supplementing with Bifidobacterium is intended to restore microbial balance and enhance gut barrier function.

Several randomized controlled trials and systematic reviews support the efficacy of certain Bifidobacterium strains (often in combination with other probiotics like Lactobacillus) in reducing the incidence and severity of AAD, especially in children and adults taking broad-spectrum antibiotics. A 2017 Cochrane review found that probiotics, including Bifidobacterium species, reduced the risk of AAD by about 50%. Some evidence also suggests a potential role in preventing C. difficile infection, though strain specificity and dosage are important factors.

While not all studies have shown benefit, and not all Bifidobacterium strains are equally effective, the overall evidence base is robust enough to support their use for this indication, particularly when using well-studied strains at adequate doses. Major clinical guidelines increasingly acknowledge the potential benefit of probiotics, including Bifidobacterium, for antibiotic-associated side effects.