Clopidogrel 是近三年來常使用的新上市抗血小板藥物，由於安全性已受到廣泛認同而被普遍使用且幾乎完全取代Ticlopidine，其腸胃道副作用亦明顯少於 Aspirin；雖然安全，但近年來仍不乏該藥物所造成的血液病變，例如TTP(thrombotic thrombocytopenic purpura)及HUS(hemolytic uremic syndrome)，但目前僅有一病例報告造成嚴重性單獨血小板減少症。我們報告一位患者在服用Clopidogrel一個月後，出現嚴重性單獨血小板減少情形，期間並未使用其他可能導致血小板減少之藥物，亦無任何臨床證據顯示為TTP、HUS或DIC。除了入院當天輸血小板八個單位之外，我們並未給予病患其他相關的治療，血小板數目於停藥後100個小時內迅速而明顯的上昇，並回到正常範圍。

　　　　　Clopidogrel is a new oral antiplatelet agent with structure and mechanism of action similar to ticlopidine. It has replaced ticlopidine for many years due to significantly lower side effects and simpler dosing regimen. Cases of thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS) associated with clopidogrel were reported in recent years, but only 1 case of isolated profound thrombocytopenia associated with clopidogrel was ever reported. We present our experience with a case of severe isolated thrombocytopenia without evidence of TTP and HUS after clopidogrel administration. No drug possibly associated with thrombocytopenia was prescribed concomitantly. Platedlet count recovered rapidly after discontinuation of clopidogrel and 8 units of platelet transfusion.