Sudden chills and shivering may be related to physiologic factors such as ambient temperature, or pathologic factors such as infectious diseases. 1. Physiological factors Sudden changes in ambient temperature, entering a cold environment, wearing too little clothing, etc. can cause sudden chills and shivering, which can improve on its own by adding appropriate clothing and raising the ambient temperature. 2. Pathological factors Commonly seen in influenza, acute pyelonephritis, meningitis, encephalitis, viral pneumonia, etc., which may lead to sudden chills and shivering. For the above infectious diseases, under the stimulation of the infectious source, it is easy to cause high fever symptoms. The patient’s body temperature rises sharply, and chills and shivering occur just before the rise. Sudden chills and shivering, even with other discomforts, if physiological factors can be ruled out, it is recommended to consult a doctor in time for examination to clarify whether there are any pathological factors, and then carry out targeted treatment.