Rongtong Dictionary · Single Herbs

Ginkgo Leaf (Yinxingye): Textual History, Nut versus Leaf, EGb761 Pharmacology, and the Limits of the Evidence

Published and reviewed 2026-07-08

Ginkgo is a 'living fossil' as old as the dinosaurs; its seed (the ginkgo nut) has long been used, but what conquered the world is the modern standardized leaf extract (e.g., EGb761). It is no 'brain-boosting, memory-improving' symbol — a large trial found ginkgo did not prevent dementia or Alzheimer's disease, and its bleeding-risk interactions cannot be ignored.

1. Names and origins: from the ginkgo nut to the modern comeback of the leaf

Ginkgo is among Earth's oldest surviving tree species, a 'living fossil' that outlasted the dinosaurs. In Chinese materia medica the part first used was the seed — the ginkgo nut (baiguo) — not the leaf. The nut's name appears by the Song–Yuan period and is formally recorded in Li Shizhen's Bencao Gangmu, which notes that cooked it warms the lung, boosts qi, and calms wheezing, while warning that eating too much causes abdominal distension and that in children excess can provoke convulsions — the ancients already knew its toxic boundary.

Intriguingly, ginkgo's modern lead role belongs not to the nut but to the leaf extract. In the later twentieth century, standardized leaf extracts (notably EGb761) were developed in Germany and elsewhere for circulation and cognition, sweeping the world — so this 'ancient yet young' drug staged its modern comeback in the form of the leaf. This split — the fruit of old, the leaf of today — is the first key to understanding ginkgo.

2. Source and authenticity: separating the nut and the leaf

The Chinese Pharmacopoeia lists two items: 'ginkgo nut' (baiguo), the dried ripe seed of Ginkgo biloba, and 'ginkgo leaf' (yinxingye), its dried leaf. From the same tree but different parts, they differ utterly in composition and safety and must never be conflated. China is ginkgo's homeland, with famed production in Shandong (Tancheng), Jiangsu (Taixing), and Guangxi (Lingchuan); large-scale leaf cultivation and extraction have even created dedicated 'leaf-use ginkgo' systems.

The pharmacopoeia assays total flavonol glycosides and terpene lactones in the leaf — precisely the core of standardized extracts. Standardized extracts (e.g., EGb761) typically specify about 24% flavonoid glycosides and 6% terpene lactones, and strictly limit the toxic ginkgolic acids — the key divide between a 'natural leaf' and a 'standardized, drug-grade extract.'

3. Actions and combination: astringing the lung to calm wheezing, and invigorating blood

The ginkgo nut is sweet, bitter, astringent, neutral, toxic, entering the lung; its traditional actions are astringing the lung to calm wheezing and checking discharge/urination — it joins ephedra and scutellaria for wheezing cough (Dingchuan Tang pairs ginkgo nut with ephedra) and joins dioscorea and euryale for vaginal discharge. The leaf is sweet, bitter, astringent, neutral, entering the heart and lung; its traditional actions are summarized as invigorating blood, freeing the collaterals, transforming turbidity to lower lipids, and astringing the lung — modern use is chiefly of its extract.

It must be stressed: the nut's 'astringe the lung, calm wheezing' and the leaf's (extract's) 'invigorate blood, free the collaterals' are two different application logics — the former a toxic seed in traditional decoctions requiring strict dosing and combination, the latter a standardized extract in a modern evidence context. Lumping them as 'ginkgo is healthy' is a common error.

4. How the physicians used it: parsing the nut's 'effect' and 'toxin'

Physicians' handling of the ginkgo nut always wove together efficacy and toxicity. The Bencao Gangmu records the nut's warming, wheeze-calming, urine-checking effects while repeatedly stressing its toxin — 'too much causes distension,' children especially warned, poisoning able to cause coma and convulsions. Ming physicians paired ginkgo nut with ephedra in Dingchuan Tang — one astringing, one dispersing — borrowing the nut to astringe the lung and calm wheezing while restraining ephedra's over-dispersion, a model of combination taming toxin while enhancing effect.

This traditional insight — that the effective is also toxic, and using a toxin requires measure — mirrors modern safety assessment: the nut's ginkgotoxin (MPN) can poison, while leaf extracts strictly limit ginkgolic acids. From the ancients' warning that 'eating many nuts causes convulsions' to modern ginkgolic-acid limits, humanity's understanding of ginkgo's 'boundary of effect and toxin' travelled a long road from experience to quantification — a reminder that with ginkgo, the safety boundary is always as important as the effect.

5. Chemistry and pharmacology: flavonoids, terpene lactones, and reading EGb761

The leaf's actives are chiefly flavonoids (ginkgo flavonol glycosides) and terpene lactones (ginkgolides A/B/C and bilobalide); the former relate to antioxidant activity, while the latter — especially ginkgolide B — antagonize platelet-activating factor (PAF). Standardized EGb761 is set to about 24% flavonoids and 6% terpene lactones, with ginkgolic acids limited.

NCCIH's evidence conclusions are notably cautious: ginkgo has not been shown to prevent or slow dementia — a large trial found 240 mg/day did not reduce dementia or Alzheimer's in older adults; benefit for mild cognitive impairment is unclear, effects on cognition in healthy people are uncertain, and much research is low quality. Evidence for anxiety, PMS, and vertigo is small and inconclusive, and ginkgo has shown no benefit for preventing heart disease, lowering blood pressure, or treating tinnitus. Mechanistic PAF antagonism and antioxidant action are not clinical benefit.

6. From nut to EGb761: slices, extracts, injections, and international supplements

Ginkgo's product range spans tradition and modernity. Traditionally the nut enters formulas like Dingchuan Tang, requiring processing and dose control; in modern practice, leaf extract is made into tablets, capsules, oral liquids, and even injections (ginkgo leaf extract injection, a strictly monitored injectable) for circulation-related indications. Internationally, ginkgo leaf extract is among the best-selling botanical supplements, often labelled EGb761 or '24% flavonoids / 6% terpene lactones.'

Key points: the toxic nut and the leaf extract are entirely different things; a standardized extract differs greatly from plain 'ginkgo-leaf tea' in composition (especially ginkgolic-acid control) and safety; and injections carry specific indications and adverse-event monitoring requirements demanding medical supervision. The three streams of evidence and risk must not be conflated.

7. Dose, processing, and pharmacopoeial use (for professional reference)

The Chinese Pharmacopoeia gives a usual decoction dose of 5–10 g for the ginkgo nut (crushed; raw nut is toxic and must be cooked and strictly limited, with special caution in children) and 9–12 g for the leaf. Modern leaf-extract products follow their labelled doses. Nut and leaf differ in action, toxicity, and use and are not interchangeable. The dose range is given to explain the standard, not as individualized advice; the nut must never be taken raw or in excess.

8. Safety boundaries and interactions

For most adults, moderate oral doses of ginkgo leaf extract are likely safe, but it may increase bleeding risk; caution is needed with anticoagulant/antiplatelet drugs (warfarin, aspirin), around surgery, and in bleeding disorders. Raw or excess ginkgo nut contains toxic ginkgotoxin (MPN), which can cause nausea, vomiting, seizures, and even life-threatening poisoning, with children especially sensitive — it must be cooked and strictly limited. Ginkgo may also interact with some hepatically metabolized drugs. People on multiple drugs, with bleeding risk, or facing surgery should consult a clinician first; stop and seek care for bleeding tendency, headache, or allergy.

9. How to judge whether a claim about ginkgo is credible

• Does it distinguish the toxic nut — the leaf — the standardized extract (e.g., EGb761) — the injection?
• Does it separate traditional lung-astringing/blood-invigorating from modern clinical evidence?
• Does it state honestly that a large trial found no dementia prevention and that most cognitive research is low quality?
• Does it flag ginkgo's bleeding risk and anticoagulant interactions?
• Does it stress the nut's toxicity, dose control, and contraindication in children?

Educational content only. It does not provide a diagnosis, prescription, or individualized treatment recommendation. The pharmacopoeial dose range is given to explain the standard, not as a basis for self-medication. Seek qualified care for persistent or urgent symptoms.