Most babies have cold hands and feet and fever after an external sensation. Since babies are in a stage of rapid growth and development, the ability to coordinate and regulate the functions of the whole body is limited, and when they get sick, their body functions further decline and their limbs do not circulate well, so they will have cold hands and feet. When the fever, the disease itself needs to consume a lot of energy in the body, at this time the baby needs to mobilize the body’s energy to fight the damage of the disease and repair the body, the peripheral circulation will be insufficient, then there is a hot body and cold extremities. Secondly, because the development of the pediatric nervous system is very immature, the poor regulation of the plant nerves, fever and sweating, sweat in the process of evaporation will take away the heat of the baby’s hands and feet, will feel cold. Infants and young children are weak when they are sick, plus the fever will accelerate the loss of body water, the relative lack of blood, which is also one of the reasons for the aggravation of cold hands and feet. Therefore, when a baby has a fever, parents must pay attention to keeping the baby warm, replenish water and nutrition, and give adequate sleep time, generally after the fever subsides, the cold hands and feet will return to normal. As long as the overall mental state is normal, parents need not worry too much. If the fever does not subside, or if the fever is repeated for more than 3 days, it is necessary to go to the hospital for examination and treatment.