Purpose of the study: A randomized, triple-blind, pilot clinical trial has been designed to evaluate the effectiveness of trehalose on reducing the symptoms in AD patients. Study intervention: twenty patients with Alzheimer's disease were randomly divided into an intervention and a control group. Trehalose will be administrated intravenously (15 g/week) for 12 weeks in the intervention group and the control group will be received normal saline as a placebo.