Yellow urine in infants may be caused by physiological factors such as drinking too little water and sweating too much, or it may be caused by other factors such as hemolysis in newborns, congenital biliary atresia, and taking medications. 1. Physiological factors: if infants usually drink too little water or sweat too much due to hot weather, this will make the urine concentrated, the patient will appear yellow urine symptoms. 2. Neonatal hemolysis: neonatal hemolysis may be caused by mother-child blood type incompatibility, the patient will have yellow skin sclera, urine color deepening, anemia, edema and other manifestations. Therefore, infants with neonatal hemolysis will show yellow urine. 3. Congenital biliary atresia: the etiology of congenital biliary atresia is not yet clear, and some studies have shown that it may be related to heredity, placental developmental abnormalities, genetics and other factors. Patients will show yellow-brown urine, yellow skin sclera, white clay-colored stools, etc. So infants with congenital biliary atresia will show yellow urine. 4. Other: infants taking vitamin B complex and other drugs or acidosis, erythrocytosis, hereditary spherical erythrocytosis will also appear in the symptoms of yellow urine. Infant yellow urine may also be caused by other factors, if the physiological factors leading to yellow urine can not be treated, if the disease causes yellow urine in infants need to consult a doctor in a timely manner, in accordance with the doctor’s advice to choose the appropriate measures for treatment.