Narrator: This is Science Today. The Ginkgo tree is one of the oldest trees on Earth. Native to southeast China, these trees were around during the Mesozoic era - the time of dinosaurs - and they have a lifespan as long as one thousand years. The extract of the leaf of the tree is used to make ginkgo biloba - an herbal supplement that has also stood the test of time.

Ercoli: It stems back to as far as five thousand years ago in China and Asia and it's been prescribed in that region for asthma and respiratory problems. And then it's used widely here over the counter and it is mainly marketed to enhance attention and memory.

Narrator: Linda Ercoli, a researcher at UCLA's Neuropsychiatric Institute, has conducted a six-month study of ginkgo biloba and reported significant memory improvement in people with age-related memory impairment.

Ercoli: We found that it worked, but individuals may vary in their response or benefit to ginkgo. So we recommend that people should consult their doctor before taking ginkgo as with any herbal supplement of medication.

Narrator: For Science Today, I'm Larissa Branin.