Fainting with fever is considered to be caused by fever. When the body temperature exceeds 39°C, the brain will be seriously lacking in energy, as well as heat, and the patient will have dizziness and even fainting symptoms. Furthermore, the cause of fainting should be considered according to the patient’s age and medical history. If the elderly have chronic cerebrovascular disease, fever can lead to cerebral ischemia and hypoxia when fainting occurs, which is related to blood pressure. It can also be seen in patients with hypoglycemia, where fainting occurs in response to hypoglycemia. Patients with fever accompanied by hypoglycemia will be physically exhausted. Fainting can also occur with persistent high fever, severe lack of sleep, and insufficient body water. If a person with a history of anemia, who is deficient in qi and blood, fever will speed up the body’s basal metabolism, and fainting will occur due to weakness and reduced blood volume.