Roots of Polygala tenuifolia Willdenow have been used in humans for centuries because of its sedative effects. We previously reported that BT-11, extracted from the roots of the plant, improved memory impairments in rats, enhanced memory in normal humans, and inhibited acetylcholinesterase activities in vitro. The present study was a randomized, double-blind, placebo-controlled comparison study to investigate whether BT-11 could enhance memory in the elderly humans. We used the Consortium to Establish a Registry for Alzheimer's Disease Assessment Packet (CERAD) and the Mini-Mental State Examination (MMSE). In the elderly, the total CERAD scores were much more significantly increased in the BT-11-treated group (n=28) than in the placebo-treated group (n=25). Especially, the mean scores of word list recognition, constructional recall and praxis, and modified Boston naming test were markedly improved in BT-11-treated group than in placebo-treated group. In conclusion, BT-11 could enhance some cognitive functions including memory in the elderly humans and therefore may be used as nutraceuticals that provide health benefits, including disease prevention and/or treatment.