Brainstem encephalitis causing half of the body to be numb and unconscious is a serious complication, and full recovery is usually difficult. The numbness caused by intracranial infection may be due to cerebral edema caused by intracranial infection, resulting in the destruction of brain tissues in the functional brain area. It is necessary to identify the cause of intracranial infection, carry out anti-infection treatment, and at the same time, use mannitol for dehydration to reduce intracranial pressure, protect normal brain tissues to avoid further damage, and alleviate the symptoms of hemianesthesia in the patient. If the patient’s condition permits, rehabilitation therapy and hyperbaric oxygen therapy are needed as soon as possible to promote limb function training, but it is more difficult to completely restore the patient to the state before the onset of the disease. Clinical treatment is generally to minimize symptoms and improve the patient’s quality of life. Patients with brainstem encephalitis need to seek prompt medical attention and active treatment to help alleviate the condition, reduce the probability of complications, and improve the patient’s quality of life.