Long Gu
StarN/A (fossilized bones of ancient large mammals including Elephantidae, Rhinocerotidae, Cervidae, Bovidae, Equidae spp.)
Traditionally used for
- Headaches
- Dizziness
- Menstrual & women's health
- Sleep
- Mood & calm
- Heart & circulation
- Skin
☯ TCM Properties
Calms the Spirit and Settles Fright; Calms the Liver and anchors floating Yang; Secures Essence and Stops Leakage; Astringes to Stop Sweating; Promotes Tissue Regeneration and Heals Sores
Traditional Chinese Uses
Long Gu (dragon bone, fossilized mammal bone) is a cool, astringent mineral substance used to calm the Liver and Spirit, anchor Yang, and prevent leakage of body fluids. It addresses anxiety, palpitations, insomnia, and emotional instability from Heart-Spirit disturbance, as well as dizziness and headache from Liver Yang rising. Its astringent nature is applied for excessive sweating, spermatorrhea, and vaginal discharge from deficiency. Calcined Long Gu has enhanced astringent action for external use on non-healing sores.
Used In Formulas (4)
Relationships
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Botanical Description
Long Gu, literally 'dragon bone', is fossilized mammalian skeletal material excavated from Pleistocene and earlier sedimentary deposits of China and East Asia. The material derives from the bones and teeth of extinct large mammals such as elephants, rhinoceroses, three-toed horses (Hipparion), deer, and bovids, in which the original calcium phosphate (hydroxyapatite) matrix has been variably replaced or infilled by mineral percolates, principally calcium carbonate, with traces of iron, manganese, and silica. The resulting substance occurs as dense, hard, off-white to grayish or yellowish-brown pieces, often retaining bone trabecular texture and adhering strongly to a moistened tongue due to residual porosity. Pieces are sorted, cleaned, and broken into fragments for medicinal preparation.
Active Constituents
Carbonated hydroxyapatite (bioapatite)
Calcium phosphate mineral, biogenic apatiteConcentration: Dominant phase of authentic Wuhua Long Gu from the Shanxi-Shaanxi region
This is the fossilised bone mineral itself, the diagenetically altered remains of the original bone apatite. It is the phase that carries the drug's characteristic high porosity (over 35%) and marked hygroscopicity, the basis of the traditional tongue-adhesion identification test.
Calcium carbonate (calcite)
Carbonate mineral, diagenetic infillConcentration: Variable secondary phase deposited during fossilisation
Calcite fills the pore network of the fossil during burial and is the reason existing pharmacopoeial standards, which assay calcium content alone, cannot distinguish authentic Long Gu from other calcium-rich mineral or bone material. A calcium assay is passed equally well by a fake.
Trace elements zinc and strontium
Trace metal signatureConcentration: Characteristic profile used as an authentication marker rather than a therapeutic constituent
Strontium and zinc substitute into the apatite lattice during burial and give authentic material a distinctive geochemical fingerprint. Their value is forensic: they identify genuine fossil bone of the expected provenance, not a pharmacological action.
Fluoride
Halide substituted into the apatite latticeConcentration: Elevated relative to fresh bone; markedly elevated in dinosaur-fossil adulterants
Fossil bone takes up fluoride from groundwater over geological time, converting hydroxyapatite toward fluorapatite. Older and differently sourced fossils carry more, and the fluoride-rich dinosaur fossils now circulating as Long Gu adulterants make chronic fluoride intake a real concern in a drug prescribed at 15 to 30 g and taken long-term for insomnia and palpitations.
Iron, manganese, potassium, sodium and aluminium
Accessory mineral and sedimentary contaminantsConcentration: Variable, source-dependent
Adhering sediment and secondary mineralisation contribute a variable element load that no current standard controls. Because the drug is a mineral dug from the ground rather than a cultivated crop, contaminant content is a function of the deposit, not of the manufacturer.
⚠ Drug Interactions
Tetracyclines and fluoroquinolone antibiotics
Long Gu is a calcium mineral taken in gram quantities. Divalent calcium chelates tetracyclines and fluoroquinolones in the gut lumen and substantially reduces their bioavailability; this is an established interaction for calcium salts and antacids. The extrapolation to Long Gu is by chemistry rather than by a trial of the drug itself, and the fraction of calcium that actually solubilises from fossil apatite has not been measured.
Clinical note: Separate Long Gu from the antibiotic by at least two hours, or suspend the herb for the course. Do not assume a mineral drug is inert in the gut simply because it is a fossil.
Levothyroxine, oral bisphosphonates and oral iron
The same divalent-cation chelation and gastric pH effects that make calcium supplements interfere with levothyroxine, alendronate and ferrous salts apply in principle to a gram-scale calcium mineral. Evidence is by class analogy with calcium carbonate rather than by direct study of Long Gu.
Clinical note: Dose the conventional drug on an empty stomach well separated from the decoction, and check thyroid function if a stable levothyroxine dose starts to underperform after a herbal formula is added.
Fluoride-rich dinosaur fossil and processed modern bone sold as Long Gu
Depletion of the authentic Shanxi-Shaanxi resource has left the market saturated with adulterants, principally fluoride-rich dinosaur fossils and processed contemporary animal bone. Existing standards test only calcium content, which every one of these substitutes passes. A patient taking 15 to 30 g daily of an unauthenticated fossil is taking an unspecified mineral of unspecified age at a food-scale dose.
Clinical note: Require documented provenance. Authentic material shows the characteristic porous microstructure, strong tongue adhesion and a zinc-strontium trace profile; a calcium certificate of analysis is not authentication.
Cardiac glycosides (digoxin)
Raised serum calcium potentiates digitalis effects on the myocardium, and this is a recognised caution for intravenous calcium in digitalised patients. Whether orally administered fossil apatite releases enough absorbable calcium to matter has not been measured, so this is flagged as a mechanistic possibility only, not an observed event.
Clinical note: No action required on current evidence, but a digitalised patient on a long-term high-dose mineral formula is worth a serum calcium check.
Dui Yao — Herb Pairs
The classical two-herb combinations this herb appears in, each with an action neither herb has alone.
Yin is nourished and the heart-kidney connection supported while the spirit is calmed, treating forgetfulness and insomnia.
Core pair of a classical formula — Kong Sheng Zhen Zhong Dan, Bei Ji Qian Jin Yao Fang (Sun Simiao)
Two heavy settling substances that together anchor floating yang, calm the spirit and astringe leakage, more effectively than either alone.
Palpitations, insomnia, spontaneous or night sweating and seminal emission from yin-yang disharmony.
Core pair of a classical formula — Gui Zhi Jia Long Gu Mu Li Tang, Jin Gui Yao Lue (Zhang Zhongjing)
Tonifying the Kidney and securing essence combined with heavy settling astringency, the pair stops enuresis, frequent urination and seminal emission while calming the spirit.
Heart-Kidney disharmony with frequent cloudy urination, poor memory and a restless mind.
Core pair of a classical formula — Sang Piao Xiao San, Ben Cao Yan Yi (Kou Zongshi)
Evidence Tier
Strong evidence · 2 studiesRecorded studies by study design, strongest design at the top. This is a study-design tier only, not a GRADE rating: it does not weigh risk of bias, consistency or precision.
Systematic review / meta-analysis
1
1 verified · 0 unverified
Randomized controlled trial
0
Other clinical trial
0
Observational / case report
0
In vitro / animal
1
0 verified · 1 unverified
Other / unclassified
0
Verified: design read from PubMed for a DOI that resolves to the cited paper Unverified: taken from the study's recorded description
Clinical Studies
Taxonomic examination of longgu (Fossilia Ossis Mastodi, “dragon bone”) and a related crude drug, longchi (Dens Draconis, “dragon tooth”), from Japanese and Chinese crude drug markets
Examined 20,939 fossil fragments of market-supplied longgu held by the Museum of Osaka University; 20,886 were mammalian and 246 could be classified, falling into nine families. Japanese-market material spanned a narrower range of taxa than Chinese-market material. The authors note that longgu is the only fossil crude drug in the Japanese Pharmacopoeia, that all Japanese supply is imported from China, and that the Chinese resource is being depleted, and they propose bone of closely related contemporary animals as a substitute. This is a pharmacognostic and palaeontological identification study, not a clinical trial.
Long Gu (Os Draconis): Textual research, modern scientific evaluation, and quality control challenges
Systematic review of Chinese materia medica from the Pre-Qin to the Qing integrated with mineralogy, palaeontology and geochemistry. Confirms authentic Wuhua Long Gu as carbonated hydroxyapatite with porosity over 35%, strong hygroscopicity and a zinc-strontium trace profile, and concludes the market is saturated with adulterants including fluoride-rich dinosaur fossils and processed modern bone because pharmacopoeial standards assay calcium alone. Calls for origin verification by palaeontological and geochronological methods and for biomimetic substitutes, describing the resource as endangered.
Historical Texts
Shen Nong Ben Cao Jing
Han dynasty, compiled c. 200 CEShang Han Lun (Zhang Zhongjing)
Eastern Han, c. 200-220 CEBen Cao Gang Mu (Li Shizhen)
Ming dynasty, 1596Japanese Pharmacopoeia
Modern, twentieth century to presentReferences
- Oguri K, Nishioka Y, Kobayashi Y, Takahashi K. Taxonomic examination of longgu (Fossilia Ossis Mastodi, “dragon bone”) and a related crude drug, longchi (Dens Draconis, “dragon tooth”), from Japanese and Chinese crude drug markets . Journal of Natural Medicines (2017) [DOI]
- Xiujia S, Zhan Hua L, Yuanze G, Ganesan K, Jing L, Li L, Chao Z, Chen J. Long Gu (Os Draconis): Textual research, modern scientific evaluation, and quality control challenges . Journal of Ethnopharmacology (2026) [DOI]
This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.
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