One of the longest and most rigorous studies yet on Ginkgo biloba found it does not slow progression of dementia and does not significantly effect cognitive function or quality of life.
The study was the first to test the effects of Gingko biloba on people with dementia in a community setting in the UK and showed no significant benefit over a six-month period.
Dr Robert McCarney, lead researcher formerly of Imperial College London, says: "Current guidelines restrict the availability of pharmaceutical treatments for people with dementia on the NHS and research shows over one in 10 of people with dementia use Ginkgo biloba.
"Previous research suggested the alternative therapy has a small but significant effect, however, our findings provide the most robust evidence yet that, sadly, Ginkgo biloba is not an effective treatment for dementia."
Professor Clive Ballard, director of research at the Alzheimer's Society, says: "This is an extremely important finding. Thousands of people with dementia, who are already struggling to make ends meet, may buy Ginkgo biloba expecting an improvement in their memory. As a nation we spend over £350 million a year on 'natural remedies'."