Antiplatelet therapy does not have a direct lytic effect on the formed thrombus, but its main effect is to prevent recurrence of ischemic stroke. Antiplatelet therapy can be started 24 hours after thrombolysis. If thrombolysis is not used early, antiplatelet therapy should be used as soon as possible, usually within 48 hours of onset. Commonly used drugs are aspirin and clopidogrel. There are four risk strata for antiplatelet therapy for stroke prevention: 1. Very high risk: includes two conditions, i.e., cerebral artery stenting or other haemoplasty. after tracheoplasty, and arterial-arterial embolic events. In both cases, the plaque is prone to dislodge and dual antiplatelet therapy with aspirin plus clopidogrel is recommended. 2. High risk: refers to ischemic stroke or transient ischemic attack (TIA) with atherosclerotic arterial stenosis or significant risk factors (diabetes, coronary heart disease, metabolic syndrome, persistent smoking). At this time, if economic conditions allow, it is best to use clopidogrel monotherapy. 3.Moderate high risk: for other ischemic stroke or TIA, at this time, use aspirin or clopidogrel monotherapy. 4.Moderate risk: High risk group with only risk factors (primary prevention), use only aspirin without clopidogrel. The recommended dose of aspirin for ischemic stroke prevention in our country is 75-150 mg.