Bifidobacterium bifidum is a probiotic bacterium that has garnered some scientific attention for its potential role in supporting or alleviating symptoms of eczema (atopic dermatitis), particularly in infants and young children. The rationale behind its use is rooted in the "hygiene hypothesis" and the observation that imbalances in gut microbiota (dysbiosis) are associated with increased risk of allergic diseases, including eczema.

Several clinical studies and randomized controlled trials have investigated the effects of Bifidobacterium bifidum, either alone or in combination with other probiotic strains, on the prevention and treatment of eczema. Some studies have shown modest benefits, such as a reduction in the severity or incidence of eczema, particularly when probiotics are administered to pregnant women and/or their infants at high risk for atopic disease. For example, a 2009 study in Clinical & Experimental Allergy found that supplementation with B. bifidum, together with other strains, reduced eczema risk in infants. However, results across studies are inconsistent, and meta-analyses often report only small or statistically non-significant effects.

In summary, the use of Bifidobacterium bifidum for eczema is supported by some scientific evidence, but the overall quality and consistency of the data are moderate at best. Its use cannot be considered a primary or standalone therapy for eczema, but it may have a supportive role as part of a broader management strategy, especially in individuals with gut microbiome imbalances.