<i>Cimicifuga dahurica</i> has traditionally been used as an antipyretic, analgesic, and anti-inflammatory agent and as a treatment for uterine and anal prolapse. This study has investigated the potential beneficial effects of this medicinal plant and its components on Alzheimer's disease (AD) with a focus on amyloid beta (Aβ) production and scopolamine-induced memory impairment in mice. An ethanol extract from <i>C. dahurica</i> roots decreased Aβ production in APP-CHO cells [Chinese hamster ovarian (CHO) cells stably expressing amyloid precursor protein (APP)], as determined by an enzyme-linked immunosorbent assay and Western blot analysis. Then, the compounds isolated from <i>C. dahurica</i> were tested for their antiamyloidogenic activities. Four compounds (<b>1</b>-<b>4</b>) efficiently interrupted Aβ generation by suppressing the level of β-secretase in APP-CHO cells. Moreover, the in vivo experimental results demonstrated that compound <b>4</b> improved the cognitive performances of mice with scopolamine-induced disruption on behavioral tests and the expression of memory-related proteins. Taken together, these results suggest that <i>C. dahurica</i> and its constituents are potential agents for preventing or alleviating the symptoms of AD.