This invention provides method for the treatment and prevention of Alzheimer's disease without noticeable side effects caused to patients, comprising administering an effective amount of Monascus-fermented product including Monascus powder and Monascus beverage. The Monascus powder and beverage are prepared through specific fermentation procedures disclosed and comprise monacolins, anti-inflammation agents and anti-oxidant compounds. The Monascus compositions are extracted from fermented red mold rice (RMR).