OBJECTIVE： To investigate the role of clinical pharmacists in individualized antiplatelet therapy for a patient with subacute stent thrombosis after PCI. METHODS： Clinical pharmacists participated in the therapy for a myocardial infarction patient with diabetes， and the patient suffered from subacute stent thrombosis at the fourth day after PCI. Clinical pharmacists suggested performing clopidogrel-related gene detection [Cytochrome P450（CYP）2C19] through comprehensively analyzing the complexity of the lesion， the time of stent thrombosis， the number of stent implantations and combined diseases， etc. According to detection result （CYP2C19*1/*2）， clinical pharmacists suggested to additionally use Cilostazol tablets 50 mg，po，bid， on the basis of previous dual antiplatelet therapy； additionally use Alprostadil injection 10 μg，ivgtt，qd to improve microcirculation. Pharmaceutical care as therapeutic evaluation， ADR monitoring were performed， and medication education as medication notes and dietary adjustments were also provided. RESULTS： Physicians adopted the suggestions of clinical pharmacists； the patient was recovered and discharged from hospital. After discharge， the disease condition kept stable due to persistent aspirin+clopidogrel+cilostazol triple antiplatelet therapy. CONCLUSIONS： Drug metabolizing enzyme is an important cause of individual differences in antiplatelet effects and toxicity， and its gene polymorphism is closely related with clinical outcome and terminal event. Clinical pharmacists should play professional skill to assist physician to access and interpret relevant information， and formulate and adjust individualized antiplatelet therapy after considering disease condition， combined diseases and genotypes， so as to guarantee safe and effective drug use.