Statistics over the past 20 years show that the incidence of cerebral hemorrhage is on a decreasing trend, while the incidence of cerebral infarction is on an increasing trend. The main reason for this change is that the risk factors for cerebral hemorrhage and cerebral infarction are different. The occurrence of cerebral hemorrhage decreases as the rate of treatment and control of hypertension continues to improve, while cerebral infarction is related to multiple risk factors such as smoking, hyperglycemia, hyperlipidemia, obesity and atrial fibrillation in addition to hypertension. Medical measures to prevent cerebral infarction in patients who have never suffered from cerebral infarction are called primary prevention, and to prevent recurrence in patients who have had cerebral infarction is called secondary prevention. How does cerebral infarction occur? It is mainly due to atherosclerosis of the cerebral blood vessels, narrowing of the lumen, on the basis of which a thrombus is formed that interrupts the cerebral blood flow and necrosis of the brain tissue in the region. In another case, due to atrial fibrillation, a thrombus is formed in the left atrium, and this thrombus is carried by the blood flow to the cerebral vessels, which can also cause obstruction. The former is called cerebral thrombosis and the latter is called cerebral embolism, both of which result in cerebral infarction. How can it cause atherosclerosis? It is mainly caused by long-term hyperemia, hyperlipidemia, diabetes, obesity and aspiration, and these risk factors can cause inflammation of the intima of the arteries and lipid deposition. How can atrial fibrillation occur? Most often seen in hypertension, long-term elevated blood pressure increases the left atrium, and atrial fibrillation can occur. Of course, rheumatic heart disease, cardiomyopathy, hyperthyroidism can also occur atrial fibrillation, but this accounts for a minority of cases. Once we know the causes of cerebral infarction, prevention can be targeted. The first step is to treat hypertension and to lower the blood pressure to below 130/85 mmHg, because hypertension is the culprit of cerebral infarction. Secondly, regulation of lipids is also very important, especially the level of LDL is correlated with cerebral infarction. For primary prevention, people with higher than normal values should firstly lower their lipids through lifestyle interventions (dietary control, strengthening exercise and avoiding smoking) Lei, and if necessary, use lipid-lowering drugs. Thirdly for patients with diabetes or prediabetes should actively control blood glucose. Fourthly enteric aspirin tablets 75-150mg daily should be taken, which has anti-platelet effect and prevents thrombosis. As for the treatment of atrial fibrillation, it should vary according to the primary disease. Regarding the secondary prevention of cerebral infarction, there are two updated recommendations: antiplatelet therapy has been studied and the combination of enteric aspirin (75-150 mg) with dipyridamole (Pansentine 200 mg twice daily) is more effective. Lipid-modifying therapy, with LDL reduction to less than 2.1 mmol/L in high-risk groups and 1.8 mmol/L in patients with multiple risk factors, is very important to prevent the recurrence of cerebral infarction.