Fever without symptoms can be categorized as pathological fever and physiological fever. 1. Pathologic fever: in the early stage of certain diseases, fever is the leading symptom, and other symptoms do not appear, such as colds, viral infections, bacterial infections and so on. Certain metabolic diseases, due to the high level of metabolism, the body produces more heat, which will increase the body temperature, such as hyperthyroidism. Malfunction of the thermoregulatory center, such as heat stroke, craniocerebral injury, etc. can also lead to asymptomatic fever. 2. Physiological fever: the body temperature will rise after exercise, female ovulation and other cases. In children, fever is often seen after a full meal. Emotional excitement, sympathetic nervous excitement can also make the body temperature rise. If the fever is caused by pathological reasons, attention should be paid to timely diagnosis and treatment in hospital.