It is normal to be drowsy after a cold, either due to the cold itself or to the use of cold medicine. However, care should be taken to rule out the possibility of other co-morbidities, especially in the elderly, children and other groups. Colds are caused by viral infections, which can be combined with or secondary to bacterial infections. The body’s metabolism speeds up in the process of fighting pathogens and consumes more energy, making it easy for drowsiness to occur. In addition, due to the cold medicine contains antihistamine drug ingredients, after taking may also appear drowsiness phenomenon. These two situations are normal, with the doctor for the treatment of colds can be, usually after the cure of the cold sleepiness can be improved. However, if you have been drowsy after a cold, you should be alert to the possibility of other diseases, such as cardiovascular and cerebrovascular diseases that are common in the elderly, and central nervous system injuries in children, etc. You should cooperate with your doctor to do routine blood tests, electroencephalograms, and cranial CTs to rule out the possibility of combining with other diseases as soon as possible. If you have been drowsy after catching a cold, it is recommended that you take cold medicines at regular intervals and in strict accordance with your doctor’s instructions. If the symptoms of drowsiness have not been relieved, it is necessary to further improve the relevant examination to clarify the cause and take targeted measures.