The causes of sudden numbness of the patient’s mouth are mainly considered in the following aspects: First, if the patient has cerebral arteriosclerosis, cerebral vascular stenosis, the sudden appearance of numbness on one side of the mouth should be considered to be caused by central neuropathy, such as minor cerebral infarction, cerebral hemorrhage or transient ischemic attack, the patient may also be accompanied by facial numbness, limb numbness. Secondly, sudden numbness of the patient’s mouth may also be caused by allergy after eating, and the patient may show numbness of the whole mouth, which may be related to the patient’s eating. In the third aspect, the most sudden numbness of the patient should also be considered to be caused by peripheral neuropathy, which may easily appear when the patient is cold, windy or poorly rested.