Weakness of the left hand and foot, the most common is cerebrovascular accident, such as cerebral infarction or cerebral hemorrhage, the most common is some middle-aged and old people, usually accompanied by high blood pressure, diabetes and other basic diseases, it is more frequent, usually in addition to the left hand, the left foot suddenly weak, there will be some head symptoms, such as dizziness, headache, nausea, vomiting or accompanied by the speech is not fluent, or even aphasia. Some patients may also have symptoms of facial paralysis, such as crooked corners of the mouth. The most serious is to lead to coma, convulsions or even central respiratory depression, resulting in respiratory distress, life-threatening, so the sudden appearance of the left hand, left foot weakness, must be immediately sent to the hospital, do a cranial CT examination, if it is a cerebral hemorrhage, then the scene can be diagnosed, and if it is a cerebral infarction, according to the symptoms of the brain infarction, basically can be judged to be a cerebral infarction, it is necessary to urgently do the relevant treatments.