Q: My baby likes one particular brand of regular (cow’s milk based) formula, but to save money, I’d also like to use up my soy formula samples. Is it okay to switch back and forth between formula types?

A: You could try it, but be prepared to ditch the experiment. You might find that your infant tolerates only a particular brand or type, the one he already likes. (See our video, "How to save on infant formula", at right.)

Some babies are fussy about formula; others aren’t. Although major brands of formula are roughly equal, it’s generally recommended that you stick with the brand your baby gets used to. It’s fine to use liquid and powder interchangeably, though.

No matter what brand or type you settle on, if your baby shows signs of intolerance, such as gas, a rash, persistent vomiting, bloody stool, diarrhea, or any other unusual symptom, consult your pediatrician. You may need to switch brands or change to a hydrolyzed or soy-based formula or to a formula specially formulated to combat your baby’s issue, whether it’s diarrhea, spitting up, or colic.

See our report on baby bottles for related information.