It is not normal for a one year old baby to have a fever 4 times a month, which can be caused by a decrease in resistance secondary to illness, primary immunodeficiency disease or poorly controlled infectious disease, and requires medical attention. 1. The baby has a recent pertussis or measles infection, which can lead to decreased resistance. Parents may carry the pathogens but have no clinical manifestations due to strong autoimmunity, while babies exposed to these pathogens may develop the disease and show fever symptoms. Care should be taken to keep the affected children with balanced nutrition and avoid going to crowded places. 2. Primary immunodeficiency diseases can cause immunocompromise, resulting in the child easily infected with pathogens and fever symptoms. It is necessary to improve the immune function tests to clarify the diagnosis. 3. Infectious diseases such as septic osteoarthritis, urinary tract infections, intracranial infections, etc., can also cause recurrent fever in one-year-old babies. You can consult a doctor in time to follow the doctor’s instructions for treatment. If a one-year-old baby fever 4 times a month, it is recommended to go to the hospital combined with the baby’s clinical manifestations to improve the relevant examination, a clear diagnosis, follow the doctor’s instructions for treatment, daily life, parents should pay attention to the baby’s nutritional status, to maintain a balanced diet.