Traditionally used for
- Dizziness
- Sleep
- Mood & calm
- Nerves & recovery
- Heart & circulation
☯ TCM Properties
Calms the Spirit and Settles Fright; Clears Heat and Eliminates Irritability; Calms the Liver and Subdues Yang
Traditional Chinese Uses
Long Chi (fossilized teeth, dragon's teeth) is a heavy, cool substance used in Chinese medicine to calm the Spirit, settle palpitations, and anchor Yang. Similar to Long Gu (dragon bone), it addresses anxiety, insomnia with disturbing dreams, and restlessness from Heart-Shen disturbance. Its Liver-calming properties also extend to dizziness and convulsions from Liver Yang rising or Liver Wind. The fossilized animal origin of this substance gives it its traditional "anchoring" and weight-settling properties.
Used In Formulas (2)
Relationships
Full-screen graph →Click a node for details · double-click to expand it · Ctrl/⌘ + scroll or two fingers to zoom and pan.
Botanical Description
Long Chi (Fossilia Dentis Mastodi) is not a plant material but the fossilised teeth of various large Pleistocene mammals, principally extinct proboscideans such as mastodons and stegodonts, and to a lesser extent fossil teeth of rhinoceroses, deer, and oxen. The medicinal material consists of hard, dense, mineralised tooth fragments and crowns recovered from sedimentary deposits in central and northern China, often together with the related fossil bone material Long Gu. Pieces are heavy, mottled greyish-white, blue-grey, or brownish, with visible enamel ridges and a porcelain-like lustre on fractured surfaces. They are composed largely of fluorapatite and calcium carbonate. Pieces are sorted, brushed clean, and calcined or used raw after crushing.
Active Constituents
Fossilised enamel apatite
Calcium phosphate mineral, biogenic enamel apatiteConcentration: Enamel is the most highly mineralised tissue in the vertebrate body and survives fossilisation as the densest phase of the drug
The glossy, porcelain-like surface layer used to identify authentic Long Chi is fossilised tooth enamel. Its density is what distinguishes the drug from Long Gu, which is porous fossil bone, and the two-layer appearance of a cut surface with a visible fossilised pulp cavity is the standard pharmacognostic marker.
Fossilised dentine and secondary calcite infill
Carbonated hydroxyapatite with diagenetic calcium carbonateConcentration: The bulk of the tooth beneath the enamel, plus calcite deposited into the pulp cavity and dentinal tubules during burial
Dentine is more porous than enamel and takes up more groundwater mineral during fossilisation. It is the fraction responsible for the hygroscopicity used in the traditional tongue-adhesion test, and the reason a calcium assay alone cannot authenticate the drug.
Fluoride substituted into the apatite lattice
Halide, lattice substituentConcentration: Elevated relative to modern teeth, and higher again in older fossil material
Buried apatite exchanges hydroxide for fluoride from groundwater over geological time, the basis of fluorine dating in palaeontology. Fossil teeth therefore carry a fluoride load that fresh bone or tooth substitutes do not, which matters for a drug taken in gram quantities over months for insomnia and palpitations. The same problem afflicts Long Gu, where fluoride-rich fossil adulterants are documented.
Iron and manganese oxide staining
Diagenetic metal oxidesConcentration: Variable surface and internal staining acquired during burial
Groundwater iron and manganese give the drug its commercial grades: blue-grey to dark brown material is sold as Qing Long Chi and yellowish-white material as Bai Long Chi. The distinction is geochemical, a record of the burial environment rather than of any difference in the animal or in pharmacological activity.
Trace elements zinc and strontium
Trace metal authentication signatureConcentration: Characteristic of genuine fossil bioapatite rather than of modern bone
Strontium and zinc substitute into the apatite lattice during fossilisation and provide a geochemical fingerprint that distinguishes fossil material from processed contemporary bone. Their role is forensic rather than therapeutic.
⚠ Drug Interactions
Tetracyclines and fluoroquinolone antibiotics
Long Chi is a calcium phosphate mineral taken in gram quantities. Divalent calcium chelates tetracyclines and fluoroquinolones in the gut lumen and substantially reduces their bioavailability, an established interaction for calcium salts and antacids. The extrapolation to fossil apatite is by chemistry rather than by a trial of this drug, and the solubilised calcium fraction from fossil enamel has not been measured.
Clinical note: Separate the herb from the antibiotic by at least two hours, or suspend it for the course.
Levothyroxine, oral bisphosphonates and oral iron
Divalent-cation chelation of the same kind that makes calcium supplements interfere with levothyroxine, alendronate and ferrous salts applies in principle to a gram-scale calcium mineral. Evidence is by class analogy with calcium carbonate rather than by direct study of Long Chi.
Clinical note: Dose the conventional drug on an empty stomach well separated from the decoction, and recheck thyroid function if a stable levothyroxine dose starts to underperform.
Long Gu, processed modern animal bone and unauthenticated fossil sold as Long Chi
Long Chi and Long Gu come from the same depleted deposits and are separated only by morphology, so substitution between them and with processed contemporary bone is easy and commercially attractive. Market studies of both drugs found material spanning nine mammalian families, and the wider fossil-drug market is documented as saturated with adulterants including fluoride-rich dinosaur fossils. A calcium-content specification is passed by every one of these.
Clinical note: Require material showing the characteristic enamel sheen, a hard dense two-layer cut surface with a visible pulp cavity, and strong tongue adhesion. A certificate of calcium content is not authentication.
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
Pharmacognostic and palaeontological identification study, not a clinical trial, and the only published examination of what market longchi and longgu actually are. Of 20,939 fossil fragments held by the Museum of Osaka University, 20,886 were mammalian and 246 could be assigned, falling into nine families; Japanese-market material spanned fewer taxa than Chinese-market material. The authors record that Chinese fossil resources are being depleted and propose bone from closely related contemporary animals as a substitute, arguing that the drug's effect appears independent of the precise source taxon.
Long Gu (Os Draconis): Textual research, modern scientific evaluation, and quality control challenges
Systematic review of the sister drug Long Gu, included here because Long Chi shares its deposits, its market and its quality-control failure. It confirms authentic material as carbonated hydroxyapatite with a zinc-strontium trace profile, documents market saturation with fluoride-rich dinosaur fossils and processed modern bone, attributes this to resource exhaustion plus a pharmacopoeial standard that assays calcium alone, and calls the resource endangered.
⚠ Safety & Contraindications
Contraindications
It is not suited to combine with Gypsum Fibrosum ( shi gao ), Resina Toxicodendri ( gan qi ) or Pericarpium Zanthoxyli ( hua jiao ).
Source: Xi S, Gong Y. Essentials of Chinese Materia Medica and Medical Formulas. Academic Press/Elsevier, 2017, pp. 295–297.
Historical Texts
Shen Nong Ben Cao Jing
Han dynasty, compiled c. 200 CEBen Cao Gang Mu (Li Shizhen)
Ming dynasty, 1596Clinical convention distinguishing Long Chi from Long Gu
Song dynasty onward, and currentReferences
- 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.
📝 Notes
Public notes from the community and your own private notes on Long Chi.
No notes yet.