It's very unusual, but yes. For example, Alimentum (powder), Nutramigen (powder), and Nutramigen ready-to-feed (RTF) contain corn. Alimentum ready-to-feed (RTF) does not. So, if your baby is allergic to corn, you might want to go only with Alimentum ready-to-feed. If your baby has severe milk allergies, she may not be able to handle Alimentum or Nutramigen. These formulas contain not cow's milk as such, but hydrolyzed (broken down) cow's milk proteins, which may be well tolerated by many babies with cow's milk protein allergy. But some babies cannot take even Alimentum or Nutramigen and may have to go to an amino acid formula such as Neocate or Elecare.