Preliminary studies are underway to determine whether ginseng may help treat some degenerative brain diseases:

"Components of the herbal ginseng protect the brain against the kind of deterioration caused by degenerative diseases like Huntingdon’s, suggests a new study on rats.

Ginseng is most commonly used in the West to boost energy (increasingly in energy drinks) and to support the immune system. But there is already some evidence of its benefits to the brain. A small Chinese trial reported two years ago found that a ginseng compound improved memory scores of people suffering from stroke-induced dementia.

In the new study, a team from Baylor College of Medicine in Houston, US, investigated whether a purified form of ginseng, in which some of the herb’s active chemicals had been concentrated, could protect rats from the effects of a toxin that caused severely impaired movement and loss of neurons."