Most children are usually more mischievous, active, if suddenly sleepy, we must be vigilant, common causes are: 1, children’s upper respiratory tract infection, in the fall and winter seasons each year, the weather becomes cold is very easy to appear, the symptoms of upper respiratory tract infection in addition to the more typical symptoms such as coughing, runny nose, early on, some children will be fatigue, drowsiness; 2, children’s intracranial infections, such as encephalitis, meningitis, etc., there will be abnormal performance of the nervous system, including drowsiness; 3, children’s low immunity, a systemic infection can cause serious systemic infections, resulting in sepsis. appear abnormal performance of the nervous system, including drowsiness; 3, children with low immunity, a systemic infection will cause serious systemic infection, resulting in septicemia, the child appeared drowsiness indicates that the condition has been very serious; 4, the usual intake of micronutrients is reduced, resulting in a lack of electrolytes such as potassium, sodium, but also weakness and drowsiness; 5, malnourished children will also appear drowsiness; 6, anemic Children can also have weakness and drowsiness.