Excluding the pyrrolizidine alkaloids, however, if single-chemical exposure is only considered, our estimated upper boundary for daily exposure levels should not pose a health risk for infants. Importantly, the longitudinal proof-of-principle study only included a single mother since this highly time-resolved sampling design is difficult to implement more broadly. While we focused on the potential contribution of breast milk towards the total xenobiotic burden of a neonate in this work, it must be clearly stated that low-level chemical exposure through breastmilk must never be a factor to reduce or avoid breastfeeding. We recently demonstrated that alternatively consumed infant formula likely leads to higher mycotoxin exposure than the consumption of breast milk . This might be also true for other toxicant classes. Most importantly, the benefit of antibodies, growth factors and bioactive compounds including oligosaccharides in breast milk must be explicitly highlighted .