After weaning the baby fever may be immunity decline, body cold, medication factors, etc. influence. 1. immunity decline: baby breastfeeding period, breast milk contains immune factors can enhance the baby’s body immunity, to the baby weaned from breast milk can not be ingested from the body immunity enhancement substances, weaned during the baby and frequent crying and restlessness affects the sleep, may lead to a decline in the body’s immune system, easy to be attacked by bacteria or viruses, by the stimulation of pathogens caused by a fever. 2. body cold: weaning baby fever may not have anything to do with weaning, weaning the baby did not give the baby timely addition or subtraction of clothing, may make the baby’s body cold, cold for the human body is a kind of external stimulus, external stimulus will lead to disorders in the body’s internal environment, stimulate the body’s immune system caused by fever. 3. drug factors: weaning baby fever may not have anything to do with weaning, after weaning have to go to the hospital for vaccination, vaccine injection into the baby’s body, mobilizing the immune system to produce antibodies, this process will cause fever. After weaning the baby fever causes more, specific to go to the hospital through the examination can be judged.