A small number of babies have reactions to a protein found in cow's milk. Signs of cow's milk protein intolerance include:

• Hives.
• Swelling of the face, tongue, mouth, or throat.
• Difficulty breathing, wheezing, or asthma.
• Abdominal pain, vomiting, and diarrhea.

Most formulas contain cow's milk protein. If your baby has symptoms of a cow's milk protein intolerance, talk to your doctor. He or she may recommend trying a soy-based or hypoallergenic formula.

Some babies who have cow's milk protein intolerance are also sensitive to soy. However, soy formulas are often tried before hypoallergenic formulas (such as Alimentum or Nutramigen) because they are less expensive. If your baby continues to have symptoms after switching to a soy-based formula, he or she may need the more expensive hypoallergenic formula.

It is important to talk with your doctor continuously throughout this process of trying formulas and monitoring your baby for symptoms.