Infant formula quiets crying human newborns.

Milk (Similac), sucrose (12% wt/vol), or water were delivered to crying normal newborns once per minute for 5 minutes, in a volume of 0.1 mL/delivery. Milk and sucrose markedly reduced infant crying, and this calm persisted during the 3 minutes after substance delivery. Infants who received water were only marginally quieted, and this calm did not persist. Despite quieting agitated infants, milk did not cause them to bring their hands to their mouths during the period of milk treatment, whereas infants who received sucrose did bring their hands to their mouths. These data demonstrate that milk effectively quiets human newborns, that its quieting effects endure, and that the mechanisms that quiet and that underlie hand-in-mouth engagement are separable and independent.