1. What are the target groups for primary and secondary stroke prevention? Which target groups are suitable for aspirin use? In the prevention and treatment of cerebrovascular diseases, aspirin is mainly used for stroke prevention and acute treatment. Stroke prevention is also divided into primary prevention and secondary prevention. The current editions of the guidelines do not recommend the use of aspirin for primary prevention, but antiplatelet agents, especially aspirin, are highly recommended for secondary prevention. For secondary prevention of ischemic stroke, long-term aspirin is recommended, but care should be taken to prevent bleeding in older individuals. Regarding the primary prevention of stroke, the main target population is the hypertensive population, followed by the atrial fibrillation, diabetes and smoking population. However, current clinical studies show that ischemic stroke and hemorrhagic stroke need to be considered differently and a lot of work needs to be done. 2. What principles should be followed when recommending aspirin in the primary prevention of coronary heart disease? How can clinicians rapidly identify the target population for primary prevention with aspirin? From the perspective of primary prevention of cardiovascular disease, low-dose aspirin should be used mainly in high-risk groups. First, what is considered high risk? Are the internationally used CHD assessment tools suitable for the Chinese population? Currently, Anzhen Hospital and Fuwai Hospital in China are conducting a comprehensive assessment in the context of the actual situation in China in order to develop assessment criteria suitable for the Chinese population. Most experts suggest that the criteria for the target population of primary prevention should be relatively broad from the perspective of their own clinical practice and domestic and international guidelines. If there is no contraindication, aspirin is recommended for patients with hypertension on the basis of good blood pressure control; aspirin is recommended for patients with diabetes and abnormal glucose tolerance over 50 years old. Other risk factors (e.g., obesity, hyperlipidemia, smoking, family history of early-onset cardiovascular disease, and sedentary lifestyle) may be considered for the use of aspirin in a combination of three or more conditions. Aspirin is the most important drug for primary prevention of coronary heart disease, and no other antiplatelet drug is yet superior to aspirin in terms of cost effectiveness. 3. What principles should be followed when recommending the use of aspirin in the secondary prevention of coronary artery disease? Aspirin plays an important role in the prevention and treatment of coronary heart disease, reducing the risk of cardiovascular and cerebrovascular events in patients with coronary heart disease. The efficacy of aspirin in preventing atherosclerotic thromboembolism is positive, including acute myocardial infarction, secondary prevention after myocardial infarction, angina pectoris, and after coronary revascularization. Aspirin 75-300 mg/d should be routinely used in all patients with acute and chronic ischemic heart disease without contraindications, regardless of whether they have significant symptoms. When aspirin is used for acute myocardial infarction, the initial dose is 150-300 mg/d, which is changed to 75-150 mg/d after 3 days for long-term use. Patients after interventional therapy should be treated with aspirin 100-300 mg/d for a long time. small doses of aspirin 75-150 mg/d are equivalent to high doses but safer when applied for a long time. Aspirin is one of the most important drugs for secondary prevention of coronary heart disease, but it is far from being used in clinical practice and there is confusion about the correct use of the drug, so how to further strengthen the correct use of aspirin in secondary prevention of coronary heart disease is an urgent problem to be solved.