The condition of brain infarction patients with fever is likely to deteriorate. After a brain infarction patient has a fever, the lack of body fluid further triggers insufficient perfusion in the brain, which will aggravate the symptoms of brain infarction, and the fever tends to cause electrolyte disorder in the body, which will also lead to brain function disorder. Therefore, fever in brain infarction patients will form a vicious circle and increase the difficulty of treatment. Especially for patients with large cerebral infarcts or key parts of cerebral infarcts, such as infarcts affecting swallowing function, thermoregulatory center parts, or complications of cerebral infarcts, all of them can lead to fever symptoms, which is a manifestation of worsening cerebral infarcts. Clinically, patients with brain infarction who have fever need to follow medical advice to draw blood tests after the fever, determine the type of bacterial infection of the fever through blood culture, find sensitive bacteria, and then choose appropriate antibiotics for treatment, which can effectively control the fever as well as improve the symptoms of brain infarction. In addition, hypoglycemia or abnormal liver and kidney functions may cause the worsening of symptoms in patients with brain infarction, and the symptoms of fever need to follow medical advice to conduct laboratory tests to clarify the diagnosis and treat the symptoms.