An object of the present invention is to provide a method which is able to prevent or improve the progress of myolytic diseases such as muscular dystrophy. Such an object is able to be solved by a method where an effective dose of an inhibitor for hematopoietic prostaglandin D synthase (H-PGDS) or an antagonist to prostaglandin D receptor is administered to a patient who needs it. The present invention also provides a method for screening compounds which are able to prevent the progress of myolytic diseases and to improve it using human H-PGDS overexpressed transgenic mice.