Q: My 3 month old infant cries when she drinks her formula, and throws it up. There's a rash all over her body, including her face, and when she's not sleeping she is very irritable. The pediatrician prescribed an antacid for the vomiting and hydrocortisone cream for the rash. She has not responded to either. All in all, I have a very unhappy baby...what can you suggest?

A: This is a common response to a sensitivity to the formula baby is drinking. When all she is being given by mouth is formula, it is pretty easy to pinpoint the offending substance. I have seen this so many times and have helped parents bring the situation to a happy resolution with an uncommon approach.

I ask the parent to purchase every can of infant formula that can be found on the supermarket shelf – and to keep the receipt because all but one or two cans will be returned! Note that there are many different kinds these days...with and without iron, soy based, milk based, varying amounts and types of sugars, etc. In these tender, new bodies, any variation could make the difference at this point.

Baby and all the bags of formula are brought into my office where I do kinesiology, also known as muscle testing. For more on this and for detailed instructions on how to do this yourself, please read the chapter on food testing in my book, Gentle Healing for Baby and Child (Simon & Schuster). The principle here is to remove from the diet whatever weakens the body's electrical system.

We are able to test each can of formula (unopened) on baby's body allowing her energy field to dictate which formula tests well for her and which does not. Or, expressed another way, which formula strengthens her energy field and which weakens it. Rather than relying upon our intellect, in muscle testing, we allow the child's body to communicate its own strengths and weaknesses. It's an unequivocal response, not something that is difficult to interpret.

After having tested countless babies this way over many years of practice, I have yet to see one who didn't begin to thrive on the newly chosen formula.

If baby is not bottle-fed but is having symptomatic responses to nursing, then we need to test baby for the foods the nursing mother is ingesting and passing on through her breast milk. Identified foods will need to be eliminated from mother's diet while breast-feeding.

Often, but not always, a baby sensitive to formula may be sensitive to other foods later on. It would be wise to introduce foods slowly and one at a time to such a child, keeping a food diary of reactions. Often the child with ADD, ADHD, skin reactions, constipation, headaches, recurrent ear infections, asthma and chronic nasal congestion can be greatly helped by identifying and eliminating offending foods.

If there is a history of allergies in the family, plan on introducing foods to your baby as if he or she were food sensitive and you may avoid problems in the future. Often, as a child's immune system matures, foods can be better tolerated and what may be an issue early on, may no longer be one later.