<p>OBJECT: To provide compounds having an excellent inhibitory action of blood platelet aggregation and a good stability when formulated. CONSTITUTION: A thiazoline derivative represented by the formula: <CHEM> wherein R<1> is an alkyl group having 1 to 4 carbon atoms and R<2> is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, or a pharmaceutically acceptable salt thereof.</p>
