After cerebral infarction homocysteine should be controlled within the normal range of 5 to 15 μmol/L. The normal range of homocysteine is 5~15 μmol/L, if the value is more than 15umol/L can be defined as hyperhomocysteinemia. Homocysteine is an independent risk factor for cerebrovascular disease. If homocysteine is elevated in a patient’s blood, it can damage the endothelial cells of blood vessels, thus affecting the permeability of blood vessels, and in the long run, it can cause atherosclerosis and the formation of thrombus, which will lead to another cerebral infarction in the patient. Therefore, patients’ homocysteine should be controlled within the normal range of 5~15μmol/L. In daily life, patients should quit smoking and drinking, limit the intake of caffeine, reasonably control the blood glucose, blood pressure, blood lipids, etc., and avoid prolonged working hours or staying up all night, as well as avoid long-term use of drugs that may affect the metabolism of homocysteine, such as isoniazid, carbamazepine, etc. If patients have homocysteine elevation, it can damage the vascular endothelial cells, thus affecting the vascular permeability. If patients have homocysteine test related abnormalities, they should go to the hospital as soon as possible, and the doctor will formulate an individualized diagnosis and treatment plan according to their specific conditions.