The baby was born three days dilute, also known as dilute stool, consider may be physiological phenomenon, abdominal cold, lactose intolerance and so on. 1. physiological phenomenon: breast milk whey protein content is relatively high, the baby’s gastrointestinal function is not well developed, caused by dilution, as long as the baby’s mental state is good, no other discomfort, most of the physiological phenomenon. 2. Abdominal cold: after the birth of the baby, improper care caused by abdominal cold, gastrointestinal dysfunction, intestinal flora imbalance, etc., there will also be diarrhea. 3. Lactose intolerance: the lack of lactase in the baby’s body, or lactase activity is low, will cause the intestinal digestion and absorption of lactose is poor, diarrhea. The baby was born three days diluted, there may be other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.