Human milk oligosaccharides (HMOs) provide a main substrate to help shape the infant's gut microbiota and affect the maturation of the intestinal mucosal immune system. In our cohort, infants that received human milk with low Lacto-N-fucopentaose (LNFP) III concentrations (< 60μM) were more likely to become affected with cow's milk allergy when compared to high LNFP III-containing milk (odds ratio 6.7, 95% CI 2.0-22).