A method of dissolving or disrupting pre-formed or pre-deposited amyloid fibrils and/or inhibiting amyloid formation, deposition, accumulation, or persistence in Alzheimers disease, prion diseases and/or other amyloidoses in a mammalian subject is disclosed. In the method a therapeutically effective amount of nattokinase is administered.本發明揭露一種針對哺乳動物個體之阿茲海默症、普昂疾病及/或其他澱粉樣變性而溶解或破壞預形成或預沈積之澱粉狀蛋白纖維及/或抑制澱粉狀蛋白之形成、沈積、累積、或是持續的方法。在該方法中,投與治療有效量之納豆激酶。