Safe and effective antiseptic use in neonatal intensive care units is mandatory. High efficacy and a low number of side‐effects from chlorhexidine have permitted avoidance of the use of mercurials and iodine derivatives, but methanol use can be unsafe in extreme preterm newborns. We report two cases of chemical burn after skin cleansing, due to alcoholic chlorhexidine (0.5%) use in extremely premature infants used for umbilical catheter insertion. Although this formulation is less concerning for use in full‐term newborns, nonalcoholic preparations are preferable for use in preterm newborns.