Sleepiness in babies is not necessarily a precursor to pneumonia; fever, hypoglycemia, and encephalitis can all cause sleepiness in babies. A baby’s longer sleep time helps him/her grow and develop. However, a baby sleeping for too long may indicate abnormalities, such as the occurrence of pneumonia. When a baby has a lung infection, it may cause the affected baby to be in a hypoxic state, causing hypoxia in the central nervous system and drowsiness. For drowsiness in babies due to pneumonia, it is usually combined with fever, cough, chest tightness and chest pain. The diagnosis can be clarified by blood gas analysis, finger pulse oxygen monitoring, chest X-ray and CT examination. In addition to pneumonia, fever, hypoglycemia, encephalitis, etc. can also cause drowsiness in babies. Therefore, parents should monitor the baby’s body temperature regularly when he/she is drowsy, and keep the air circulating in the room. Give easy-to-digest food, feed regularly and observe whether the symptoms are relieved.