PLATELET AGGREGATION INHIBITOR

PROBLEM TO BE SOLVED: To provide a new platelet aggregation inhibitor relieving or preventing various symptoms caused by the platelet aggregation, and a bloodstream-improving agent and an antithrombotic agent by using the above inhibitor as an active ingredient. SOLUTION: This platelet aggregation inhibitor is provided by containing at least 1 compound selected from a group of compounds having oxygen-containing ring structures expressed by formulas (1) to (6) as an active ingredient, and the bloodstream-improving agent and antithrombotic agent containing the above compound as the active ingredient are also provided. As the platelet aggregation inhibitor, especially (R)-2-deceno-δ-lactone is preferable. COPYRIGHT: (C)2009,JPO&INPIT