One side of the corner of the mouth numbness is mainly recommended for the following reasons: first, to ask the patient, there is no recent history of trigeminal nerve damage, if belongs to the acute stage of trigeminal neuritis, there will be a side of the main numbness, because the trigeminal nerve including sensory and motor nerves, can cause one side of the face of the numbness. Secondly, the numbness of the corner of one side of the mouth, we should ask the patient whether there is dizziness, headache, choking on drinking water, there is no numbness of the same side of the limbs, weakness, we must be alert to whether there is an acute cerebrovascular disease, such as cerebral infarction, cerebral hemorrhage, at this time we need to go to the hospital to do a cranial CT or magnetic resonance imaging examination. Third, the numbness of the corner of the mouth, but also ask the patient whether the numbness is persistent or intermittent, there is no dizziness, neck pain, need to go to the cervical spine magnetic resonance examination, to understand whether there is cervical spondylosis may be.