Fever once a month in a four-year-old child is commonly seen in conditions such as recurrent respiratory infections, which are usually considered abnormal and may also be related to a variety of factors. Four-year-old children with fever once a month, can be seen in a variety of diseases, the age of the baby’s own immune function is not perfect, the respiratory and other systems are vulnerable to pathogenic attacks, such as repeated respiratory infections; especially for some of the unbalanced diet of the baby, there may be microelements and vitamins, such as deficiencies, affecting the children’s immunity, prone to the above phenomenon. It is usually considered abnormal. Four-year-old children with underlying pathologies, such as immunodeficiency diseases, congenital abnormalities of airway development (e.g., tracheobronchial softening), and other diseases are more susceptible to pathogenetic attack to develop the above phenomena. It is usually considered abnormal. Such babies are advised to actively seek medical attention and be evaluated by a specialist.