PROBLEM TO BE SOLVED: To provide a novel platelet aggregation inhibitor capable of relieving or preventing various symptoms caused by aggregation of platelets, particularly, a platelet aggregation inhibitor available more conveniently and capable of being mass-produced easily.SOLUTION: The platelet aggregation inhibitor includes at least one compound selected from the group consisting of compounds having oxygen-containing circular structures represented by formulas (1) to (3) as an active ingredient. There are further provided blood flow improving agents and antithrombotic agents each containing the platelet aggregation inhibitor as an active ingredient.COPYRIGHT: (C)2013,JPO&INPIT【課題】血小板凝集による様々な症状を軽減し、もしくは予防することができる、新規な血小板凝集抑制剤、特により簡便に入手できると共に、大量生産が容易に実現可能な血小板凝集抑制剤の提供。【解決手段】式(1)乃至(3)で示される含酸素環状構造を有する化合物群から選ばれた少なくとも1つの化合物を有効成分として含有する血小板凝集抑制剤。本発明はさらに、上記の血小板凝集抑制剤を有効成分とする、血流改善剤および抗血栓剤。【選択図】なし
