No. But your baby could be reacting to something in your diet that is passing into your milk. If your baby has physical signs of allergy or sensitivity (rash, congestion, vomiting, diarrhea, etc.), start by eliminating all dairy products from you diet for two to three weeks and see if baby's symptoms subside. This is the most common cause of these types of reactions in a breastfeeding baby. Other likely culprits are other protein-rich foods, such as soy, eggs, and fish.