An use of a pharmaceutical composition for manufacturing a drug of preventing or treating abnormal β-amyloid mediated diseases. The pharmaceutical composition comprises Artemisinin.本發明係有關於一種醫藥組成物於製備預防或治療不正常乙型-澱粉樣蛋白聚集類疾病之藥物上之用途,該醫藥組成物包括青蒿素(Artemisinin)。