Bifidobacterium species have been investigated for their potential to support or treat rhinitis, particularly allergic rhinitis, due to their immunomodulatory effects. Several randomized controlled trials (RCTs) and meta-analyses have evaluated the impact of probiotics, including Bifidobacterium strains, on symptoms of allergic rhinitis. These studies suggest that some Bifidobacterium strains may help reduce nasal symptoms and improve quality of life in individuals with allergic rhinitis by modulating immune responses, such as shifting the Th2-dominated response toward a more balanced Th1/Th2 profile and enhancing regulatory T cell activity.

However, the overall clinical evidence remains moderate at best. Systematic reviews and meta-analyses typically conclude that probiotics, including Bifidobacterium, may offer modest benefits for allergic rhinitis, but the effects are strain-specific and not consistently reproducible across studies. The heterogeneity in probiotic strains, dosages, and study designs contributes to the modest rating of the evidence. There is little evidence for the use of Bifidobacterium in non-allergic rhinitis.

In conclusion, there is some scientific evidence supporting the use of certain Bifidobacterium strains for allergic rhinitis, but the benefits are limited and not universally established. Clinical guidelines do not currently recommend probiotics as a standard treatment for rhinitis, and more high-quality, strain-specific studies are needed to clarify their efficacy.