The precursor of cerebral infarction does not include dizziness every afternoon, cerebral infarction does not have specific precursor symptoms, but the early onset of the disease can be manifested as a skewed corner of the mouth, asymmetry of the movement of the limbs on both sides, speech disorders, and sudden vertigo. 1. Skewed corners of the mouth: after cerebrovascular infarction, it may affect the function of facial nerve nuclei, which may lead to the failure of motor and sensory function of the face, and then there will be the performance of skewed corners of the mouth and numbness of the face. 2. Asymmetry of limb movement on both sides: due to the infarction of cerebral blood vessels, it will lead to insufficient blood supply to the brain tissue, which will affect the motor function of nerves, resulting in imbalance of limb strength and asymmetry of limb movement on both sides. 3. Speech disorder: cerebrovascular infarction will lead to the dysfunction of the speech center of the brain, thus causing the phenomenon of slurred speech or inability to speak. 4. Sudden dizziness: due to the infarction of cerebral blood vessels, the blood circulation of local brain tissue is insufficient, which causes sudden dizziness. Therefore, when there are signs of crooked mouth, weakness of arms and legs, speech disorder and dizziness, we should pay attention to them and go to the hospital in time.