Ginkgo

A unique species of tree with no close living relatives (a living fossil) which is believed to have nootropic properties, and is mainly used as memory and concentration enhancer, and anti-vertigo agent:

Ginkgo

In memory enhancement

Studies differ about the efficacy of Ginkgo. The largest and longest independent clinical trial to assess ginkgo biloba’s ability to prevent memory loss has found that the supplement does not prevent or delay dementia or Alzheimer’s disease. Some controversy has arisen over the conclusions drawn by some studies that were funded by a firm which marketed Ginkgo [read more here].

In dementia

Ginkgo has been proposed as a treatment for Alzheimer's disease on the basis of positive preclinical results in mice. However, a randomized controlled clinical trial published in JAMA in 2008 found it ineffective at treating dementia in humans [read more here].