Ginkgoaceae

Ginkgo biloba

Ginkgo · Maidenhair tree

No support Caution

Part used: leafseed
Native range: China. Effectively extinct in the wild; the surviving populations may all descend from cultivation
Morphology: A deciduous tree to thirty-five metres with distinctive fan-shaped notched leaves. The sole surviving species of an order that flourished before the dinosaurs, with no close living relatives at all.

What is in it

terpene trilactones ginkgolide A, ginkgolide B, bilobalide

flavonol glycosides quercetin, kaempferol

ginkgolic acids

Evidence

The GEM study followed over 3,000 older adults for around six years and found no reduction in dementia incidence. Later large trials agree. Cochrane finds no convincing benefit for cognitive decline or for tinnitus. Intermittent claudication shows a small effect of uncertain clinical value.

Safety

Generally well tolerated. The significant hazard is bleeding: ginkgolides inhibit platelet-activating factor, and spontaneous bleeding including intracranial haemorrhage is reported. Raw seeds are genuinely toxic and cause convulsions through a vitamin B6 antagonist, with poisonings recorded particularly in children.

Interactions: Additive bleeding risk with anticoagulants, antiplatelets and NSAIDs; Reported to lower efficacy of some anticonvulsants

Regulatory: Permitted as a listed medicine ingredient in Australia; standardised extract is a registered medicine in Germany.

How the traditions classify it

Chinese The seed, bai guo, is used rather than the leaf — sweet, bitter and astringent, for cough and wheezing. Western practice reversed this and uses a standardised leaf extract, which the Chinese tradition did not.

Three systems, rating the same plant. Where they disagree, none of them is correcting the others — they are separate frameworks that arrived at their categories independently.

Historical use

Cultivated around Chinese and Japanese temples for a thousand years, valued for the seed. The leaf extract is a twentieth-century German pharmaceutical development and is not a traditional preparation.

Recorded as history and attributed where possible. Long use establishes that a plant was widely used, not that it worked, and not that it was safe.

Worth knowing

Ginkgo is the best example of a preparation being sold on the authority of a tradition that used a different part of the plant for a different purpose.

Chinese practice uses the seed, for the lungs. The global supplement industry sells a standardised leaf extract, for memory. The extract is a genuine pharmaceutical achievement — a defined, reproducible product — and it has essentially nothing to do with the two thousand years of use it borrows credibility from.

The tree itself is the more remarkable fact. It is the last member of an entire order, with no living relatives closer than the conifers, and it survives largely because people planted it next to temples.

Nomenclature verified against GBIF backbone taxonomy.