Breast milk is the milk produced by the breasts (or mammary glands) of a human female to feed a child. Milk is the primary source of nutrition for newborns before they are able to eat and digest other foods; older infants and toddlers may continue to be breastfed, in combination with other foods from six months of age when solid foods should be. It's also important to note that breast milk expressed when a baby is a newborn won't as completely meet the same baby's needs when he or she is a few months older. A baby cannot actually be allergic to his mother's breast milk, but may develop an allergy or intolerance that appears to be a breast milk allergy. In most.