Research synthesisModerate evidenceModerate effect6 studies · 5 beneficial · 1 neutral · 0 harmful
Across 6 studies, 5 reported beneficial effects of Bifidobacterium animalis subsp. lactis BB-12 on reducing upper respiratory infections, with 4 reaching statistical significance. The predominant effect size was moderate, though individual study effects ranged from small to large. The most studied population was healthy infants and young children, and a specific effective dose was reported in one trial as 10 billion colony-forming units/day.
- Effective dose range: 10 billion colony-forming units/day (from one study; other studies did not report dose)
- Studied populations: Healthy infants, children aged 0-3 years, adults (from network meta-analysis), children in early childhood education settings
Caveats: Available evidence is overwhelmingly positive — clinical literature in this area is subject to publication bias (null-result studies are less likely to be published or indexed). Many studies did not report doses or had small sample sizes. One neutral study in children in early childhood education settings suggests effects may not generalize to all pediatric populations.
Generated May 18, 2026