Cerebral drowsiness has both physiological factors, such as fatigue, lack of sleep and so on. There are also disease factors, such as neurasthenia, insufficient blood supply to the brain, cerebrovascular disease. 1. Physiological factors: This is mostly caused by fatigue, lack of sleep, or work pressure, excessive brain and negative emotional interference, may also cause brain drowsiness, generally through the adjustment of the symptoms will improve on their own. 2. Disease factors: this is mostly seen in neurasthenia, cerebral arterial blood supply deficiency, cerebrovascular accidents and other diseases. (1) neurasthenia: patients mainly show the symptoms of easy brain fatigue and mental excitement, and patients can also show the symptoms of brain drowsiness. At the same time, it will be accompanied by fatigue and mental lethargy. (2) Insufficient blood supply to the cerebral arteries: due to severe atherosclerotic changes or plaques in the cervical vessels, patients may suffer from intracranial vascular supply disorders, which cause cerebral ischemia and hypoxia, and may also show symptoms of dizziness and dullness of the brain. (3) Cerebrovascular diseases: including cerebral infarction, cerebral hemorrhage and other diseases, which will lead to the central nervous system function is impaired resulting in cerebral drowsiness, often accompanied by limb weakness, dysphagia and other manifestations. The cause of cerebral drowsiness is very complex, which requires the combination of the patient’s accompanying symptoms to improve the relevant examination to clarify the cause of the disease, so as to be able to treat the cause and improve the symptoms.