Most babies do well with a cow's milk based formula (Enfamil or Similac), but you may need to change to another type of formula if your baby has an allergy to lactose or the proteins in these formulas. If necessary, consider changing formulas to those that are lactose free (Lactofree) or that are based on soy protein (Isomil or Prosobee). Another type of formula has the proteins hydrolyzed or broken down into their most basic parts to aid in digestion (Nutramigen or Alimentum).


Signs that your baby has a formula intolerance include being fussy all of the time (especially during or right after a feeding), vomiting or having diarrhea, or if they are not gaining weight. Talk with your doctor if you think you need to change your baby's formula.

You should probably not change formula type if your baby has colic or if he is spitting up a lot, but gaining weight well. These conditions require no treatment.

Most importantly, do not change to a low iron formula. These types of formula do not contain enough iron to meet your baby's nutritional needs and can lead to iron deficiency anemia. It is important to remember that iron has never been shown to cause problems with constipation, colic, or spitting up.