Two and a half year old children often have fever, mainly due to: repeated infections, autoimmune diseases, tumors and so on. 1. Repeated infections: due to the child’s age, the body’s immunity is relatively low, it is easy to be infected by bacteria, viruses, parasites and other pathogenic bacteria, and then produce fever symptoms. For example, acute gastroenteritis, upper respiratory tract infections will have different degrees of fever. 2. Autoimmune diseases: such as Kawasaki disease, systemic lupus erythematosus, etc., will affect the normal function of the thermoregulatory center, which will also lead to frequent fever symptoms. 3. Tumors: such as lymphoma, leukemia, etc., will lead to a decrease in the body’s normal white blood cells as well as decreased immunity, and then also prone to frequent fever symptoms. All in all, two and a half year old children often have a fever, it is recommended to go to the hospital in a timely manner, a clear diagnosis and symptomatic treatment, and in the daily life of the child to supplement the nutrients, to improve the body’s immunity.