It is an object of the present invention to provide a method for determining inflammatory diseases including myocardial infarction as a typical example, which involves identifying polymorphisms associated with myocardial infarction and using the gene polymorphisms, an oligonucleotide that can be used for the method, a kit for diagnosing inflammatory diseases, a therapeutic agent for inflammatory diseases, and the like. The present invention provides a method for determining an inflammatory disease, which comprises detecting at least one type of gene polymorphism existing in a proteasome subunit α type 6 gene.