The drowsiness period after craniotomy is mainly caused by intracranial cerebral edema that occurs in patients after surgery. The serious consequence of cerebral edema is the increase of intracranial pressure. In order to make the patient pass the drowsiness period smoothly, it is recommended to monitor the intracranial pressure routinely. If the intracranial pressure is not high, the patient’s drowsiness can usually be relieved within two weeks because the cerebral edema slowly subsides or even recovers completely in about two weeks. If the intracranial pressure continues to rise during intracranial pressure monitoring and drowsiness occurs, this situation requires high attention. This drowsiness is pathological in nature. If the intracranial pressure continues to exceed 25 mmHg and treatment with dehydrating medications is unsatisfactory, then surgery should be considered again, which is primarily aimed at decompressing the brain in order to keep the intracranial pressure normalized.