The causes of numbness of the corners of the mouth are as follows: 1, intracranial cavernous cerebral infarction: especially the thalamus, and some of the basal ganglia near the thalamus, which is easy to lead to small cavernous infarcts, resulting in numbness of the corners of the mouth phenomenon. 2, damage to the trigeminal nerve: because the sensation of the face is innervated by the trigeminal nerve, the trigeminal nerve can lead to the phenomenon of numbness of the corners of the mouth. 3, tumors in the cranium: the early stage of tumors pressing the tissues of the brain, which may cause Numbness of the corners of the mouth. In short, the numbness of the corners of the mouth, do not take it lightly, you need to go to the neurology department of the hospital immediately to consult, through the relevant examination to make a clear diagnosis as soon as possible, to decide the next step of the treatment program.