The numbness of the right lower lip and chin may be viral infection, facial neuritis or ischemic cerebrovascular disease, which needs to be analyzed specifically. 1. Viral infection: localized viral infection around the mouth, such as common herpes virus infection, may cause numbness of the right side of the lower lip and chin, often accompanied by the appearance of perioral herpes, blood routine, herpes fluid smear can assist in the clear diagnosis. 2. Facial neuritis: that is, we often say facial paralysis, may appear right lower lip and chin numbness, clinical classification into central and peripheral type, may also be accompanied by nasolabial folds become shallow, drooping corner of the mouth and other symptoms, cranial CT and magnetic resonance can be assisted to exclude organic lesions, the function of cerebral nerves can be used to assist in the definitive diagnosis. 3. Ischemic cerebrovascular disease: ischemic cerebrovascular disease can be due to local cerebral blood supply is insufficient, resulting in neurological dysfunction, the right side of the lower lip and chin numbness, can also be accompanied by dizziness, headache and other symptoms, cranial CT or MRI can assist in the definitive diagnosis. There are many causes of numbness of the right side of the lower lip and chin, if the above situation occurs, it is recommended to immediately consult the doctor, timely treatment, to avoid delaying the condition.