Clopidogrel is a platelet aggregation inhibitor witch prevents thrombotic events in patients with atherosclerotic vascular disease. To date, 4 to 30 % of patients are considered as poor, low or non-responder to this therapeutic. However, drug-drug interactions may lead to decrease the clopidogrel responsiveness. Many arguments are in support to a drug-drug interaction between clopidogrel and fluoxetine (selective serotonin reuptake inhibitor). On the pharmacokinetic level, fluoxetine inhibits the cytochroms involved in the production of clopidogrel active metabolite. On the pharmacodynamic level fluoxetine could increase the risk of hemorrhage by inhibiting the serotonin platelet reuptake and thus enhance the antiplatelet effect of clopidogrel.