Breastfeeding is the best source of infant nutrition. Good maternal nutrition is important for the preparation and maintenance of breast-feeding. When thinking of using infant formula, a mother should be aware of (i) the financial and social implications of formula feeding, (ii) the difficulty of reversing the decision not to breast-feed and (iii) the care that must be taken to prevent partial formula feeding from interfering with lactation. In addition, proper preparation of powder or concentrated liquid infant formula requires the use of boiled water for the purposes of mixing formula and cleaning implements and the manufacturer’s mixing instructions must always be followed. Improper mixing or preparation may make a baby sick. A healthcare professional should always be consulted before initiating formula feeding.