Breast milk is the safest, most economical and convenient food for babies, and can meet the needs of growth and development of babies up to 6 months of age, with the right ratio of protein and minerals, which are easily digested and absorbed by babies. Breastfeeding improves infant immunity and prevents diarrhea to reduce infant’s allergies. However, some breastfed babies also have eczema, diarrhea, blood in the stool, etc., which means that babies are allergic to breast milk. There are three main symptoms of breast milk allergy. The first is the digestive symptoms, where the baby has repeated vomiting, diarrhea, bloating, constipation, and blood in the stool. The second is skin symptoms, the baby will appear eczema, acute urticaria. The third is respiratory symptoms, the child has frequent unexplained coughing and sneezing, and severe asthma. The incidence of breast milk allergy is lower than formula feeding and the symptoms are relatively mild. Infant food allergies are actually mainly protein allergies. Dietary proteins such as milk and eggs ingested by the mother can enter the baby’s body through breast milk and induce allergies in the baby, but it is not recommended to just stop breastfeeding. If the mother avoids the allergic food and the symptoms are relieved, she can continue breastfeeding. When the baby’s symptoms do not improve after the mother avoids the diet and the growth is delayed, the baby needs to change to a special formula under the guidance of a doctor.