A baby not drinking milk for a day may be caused by anorexia, flatulence or other illnesses. 1. Anorexia: A baby who doesn’t drink milk for a day may be in the anorexia stage. Anorexia mostly occurs around 3 to 6 months of age, and the reason is still unclear. Parents should pay special attention to their children’s milk intake to avoid poor growth and development. 2. Flatulence: If the baby swallows too much air during feeding by the parents due to improper feeding, which leads to flatulence, the baby may not drink milk for a day. 3. Other diseases: If the baby suffers from colds, gastroenteritis and other diseases or intestinal allergies, it may also not drink milk for a day. The baby does not drink milk a day, 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.