Heat stroke can cause fever. Heat stroke occurs when the ambient temperature is too high, usually over 35°C, and when the humidity is too high and ventilation is poor. In addition, heat stroke can also occur after a period of physical labor or strenuous work in the hot sun without any sun protection or cooling measures. Because high temperature can cause dysfunction of the thermoregulatory center, the heat balance in the body will be out of balance, causing a large accumulation of heat in the body, but the heat dissipation is reduced, and the heat production of the body is greater than the heat dissipation, resulting in fever symptoms. It is most often seen in elderly, frail, obese, heavy alcohol consumption, loss of water, salt, wearing tight, impermeable clothing, and in patients with previous hyperthyroidism, diabetes, cardiovascular disease, extensive skin damage, lack of sweat glands, or use of atropine or other anticholinergic drugs that affect sweat gland secretion. Patients with mild heat stroke usually experience a marked increase in body temperature, often above 38°C, with profuse sweating, burning skin, flushing, and in severe cases, a rapid heartbeat and a drop in blood pressure. If treated promptly, symptoms can usually recover within a few hours. When severe heat stroke occurs, especially heat stroke, the body temperature usually exceeds 41°C. Patients have dry skin, no sweating, accompanied by severe dizziness, headache, and even impaired consciousness, and in severe cases, blood pressure may drop until shock, or cause heart failure, acute pulmonary edema, acute cerebral edema, liver and kidney failure, and extensive microvascular intravascular thrombosis, so the prognosis is very poor, with a mortality rate of 5%-30%. Emergency resuscitation treatment is required, such as various cooling measures, including physical and pharmacological cooling, and the speed of cooling usually determines the patient’s prognosis.