Sudden drowsiness in children is considered to be caused by physiological or pathological factors. Physiological factors, such as lack of sleep; pathological factors, such as bacterial meningitis and other neurological infections, can cause drowsiness in children. 1. Physiological factors: when children have insufficient sleep or fatigue, it will lead to an increase in sleep time and prolonged sleep time due to the need of the body, in this case, children are generally in good condition, with normal growth and development, and the subsequent sleep time will return to normal. 2. Pathological factors: when children suffer from neurological infections such as bacterial meningitis, viral encephalitis, etc., it is easy to have neurological abnormalities and lead to drowsiness, in addition to drowsiness, there can be fever, headache, vomiting and other symptoms; in addition, some other more serious infections, such as pneumonia, caused by fever or even hyperthermia, can be accompanied by drowsiness. Children’s sudden drowsiness, there may be other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.