4 months baby fever 37.7 ℃ recommended to reduce the baby’s clothing cover, appropriate to increase the number of breastfeeding or amount of milk, monitoring and observation of the baby’s temperature changes and mental condition, if necessary, timely access to medical care. 4 months baby fever to 37.7 ℃ belongs to low fever, you can keep indoor ventilation, indoor temperature control at 24 ℃ or so, appropriate to the baby to reduce clothing cover to help dissipate heat. In addition babies also need to increase water intake, 4-month-old babies can increase the frequency of breastfeeding or formula feeding to intake of water. Regularly monitor your baby’s temperature, and use acetaminophen or ibuprofen under doctor’s supervision to reduce fever if the temperature continues to rise above 38.5 degrees Celsius. It is also necessary to pay attention to the baby’s mental and sleep conditions, if there is a lack of energy, persistent crying, it is recommended to seek medical treatment.