Long Gu (Os Draconis): What It Is, Benefits, Uses, and Risks

You might stumble across “Long Gu” in discussions about Traditional Chinese Medicine (TCM). Sometimes mistakenly called Fossilia Ossis Mastodi, its more common scientific name is Os Draconis. And no, despite the dramatic name which translates to “Dragon Bone,” this isn’t sourced from mythical creatures!

So, what exactly is this intriguing substance, and why has it been used in TCM for centuries? Let’s dig into what Long Gu is, its traditional applications, what modern science says, and the important safety considerations.

What Exactly Is Long Gu (Os Draconis)?

Think natural history rather than fantasy. Long Gu is actually the fossilized bones of large, ancient mammals that roamed the earth millions of years ago¹.

• Source: Primarily from prehistoric animals like elephants (e.g., Stegodon orientalis), rhinoceroses, horses, deer, and cattle².
• Appearance: It typically comes in irregular, heavy chunks or pieces. The color ranges from greyish-white to yellowish or brownish, often with visible fossilized bone texture or even tooth fragments. Some high-quality types, called “Wu Hua Long Gu” (Five Flower Dragon Bone), have distinct colorful patterns.
• Key Component: Chemically, it’s mostly calcium carbonate (CaCO₃) and calcium phosphate (Ca₃(PO₄)₂), similar to regular bone, but fossilized. It also contains trace minerals like iron, magnesium, potassium, and silicon³.
• Forms Used: In TCM, you’ll encounter two main forms⁴:
  • Sheng Long Gu (Raw): Cleaned, dried, and crushed fossil bone.
  • Duan Long Gu (Calcined): Raw Long Gu heated intensely until red-hot. This process changes its chemical structure (converting some calcium carbonate to calcium oxide) and its therapeutic properties according to TCM.

Summary: Long Gu is the fossilized bones of prehistoric mammals like elephants and rhinos. It has an irregular shape and various colors. Mainly composed of calcium compounds and trace minerals, it comes in raw and calcined forms in TCM.

Traditional Uses in TCM: More Than Just Old Bones

In the world of TCM, ingredients are understood by their inherent properties (like taste and temperature) and the body systems (meridians) they influence. Long Gu is considered sweet, astringent, and neutral in temperature, primarily acting on the Heart, Liver, and Kidney meridians⁵.

For centuries, TCM practitioners have used Long Gu for several key purposes:

Calming the Spirit (Zhen Jing An Shen)

This is perhaps its most famous use. It’s employed to anchor and calm the mind and spirit, traditionally used for conditions like⁶:

• Anxiety and restlessness
• Palpitations (feeling your heart race or flutter)
• Insomnia and frequent dreaming
• Seizures or convulsions (Sheng Long Gu is generally preferred for this)

Subduing Rising Liver Yang (Ping Gan Qian Yang)

In TCM theory, certain symptoms like dizziness, vertigo, irritability, and headaches can be caused by an imbalance described as “Liver Yang Rising.” Long Gu’s heavy nature is thought to help suppress this rising energy⁷.

Astringent Action (Shou Lian Gu Se)

Think of this as helping the body “hold onto” essential substances and stop unwanted leakage or discharge. It’s used for⁸:

• Excessive sweating (daytime or nighttime)
• Chronic diarrhea
• Spermatorrhea (involuntary emission) or premature ejaculation
• Excessive vaginal discharge (leukorrhea) or uterine bleeding (Duan Long Gu, the calcined form, is considered more potent for this)

Promoting Tissue Healing (Sheng Ji Lian Chuang)

When applied topically as a powder (usually the calcined form), Duan Long Gu is used to absorb moisture, protect wounds, and promote the healing of non-healing ulcers, sores, or weeping eczema⁹.

Summary: In TCM, Long Gu has various traditional uses. It calms the spirit, subdues rising Liver Yang, has an astringent action, and promotes tissue healing. Different forms are used for different conditions like anxiety, sweating, and wound healing.

Potential Benefits: What Does Modern Science Say?

While Long Gu has a long history of traditional use, high-quality scientific evidence from human clinical trials is still limited. Much of the modern research involves laboratory (in vitro) or animal studies, often looking at complex TCM formulas containing Long Gu, making it hard to isolate its specific effects.

Here’s what some preliminary research suggests:

• Sedative and Anti-Anxiety Effects: Some animal studies indicate that extracts from Long Gu or formulas containing it might have calming and anti-anxiety properties. Researchers theorize this could be linked to its calcium content or trace minerals influencing neurotransmitter activity, but the exact mechanism isn’t fully understood¹⁰.
• Anticonvulsant Potential: Animal models have shown some potential anticonvulsant activity, aligning with its traditional use for seizures. Again, more research is needed¹¹.
• Astringent and Wound Healing: The high calcium content, especially in calcined form (which contains calcium oxide), likely contributes to its topical effects. Calcium oxide is alkaline and drying, which can help absorb fluids from wounds. Calcium ions also play a role in blood clotting. This provides a plausible scientific basis for its traditional topical use¹².  

Important Caveat: It’s crucial to remember that these are potential mechanisms based on limited evidence. Long Gu is not a replacement for conventional medical treatments for conditions like severe anxiety, epilepsy, or major bleeding.

Summary: Modern science on Long Gu has limited human clinical evidence. Some animal and in vitro studies suggest potential sedative, anticonvulsant effects and astringent/wound – healing properties. But it’s not a substitute for conventional treatments.

Risks and Side Effects: What to Watch Out For

Using Long Gu isn’t without potential risks:

1. Heavy Metal Contamination: This is a significant concern. Because it’s a fossil dug from the earth, Long Gu can absorb heavy metals like lead, arsenic, and cadmium from its environment over millions of years. Using Long Gu from untested or unreliable sources poses a serious health risk. Always ensure it comes from reputable suppliers who test for contaminants¹³.
2. Digestive Issues: Its heavy, mineral nature, particularly the calcined form, can cause constipation due to its astringent effect. Some people might experience indigestion or stomach discomfort¹⁴.
3. Contraindications: TCM theory advises against using Long Gu in cases of “damp-heat” or “excess heat” conditions without underlying deficiency. It should be used cautiously in people with severe constipation.
4. Potential Drug Interactions: The high calcium content could theoretically interfere with the absorption of certain medications, such as tetracycline antibiotics or bisphosphonates (used for osteoporosis). Discuss Long Gu use with your doctor if you take other medications¹⁵.

Summary: Using Long Gu has risks. It may have heavy metal contamination from untested sources. Can cause digestive issues like constipation. Has contraindications in some conditions. May interact with certain meds, so consult doctor if taking other drugs.

How Is Long Gu Used Today?

• In TCM Practice: Long Gu remains a commonly used ingredient within the framework of Traditional Chinese Medicine. Licensed TCM practitioners may include it in personalized herbal formulas (decoctions, powders, pills) based on a traditional diagnosis. They should be knowledgeable about quality sourcing and potential risks.
• Not in Conventional Medicine: You won’t find Long Gu prescribed by mainstream Western medical doctors. Its use is confined to traditional and alternative medicine systems.
• Regulation and Conservation: Being a fossil, Long Gu raises conservation concerns. Its availability can be limited, and it has been removed from some later editions of the official Pharmacopoeia of the People’s Republic of China, partly due to resource protection and quality control challenges¹⁶. Research into potential substitutes is ongoing.

Quick Q&A about Long Gu

• Q: What is Long Gu mainly used for in TCM?
  • A: It’s primarily used to calm the mind and spirit (for anxiety, insomnia, palpitations), settle Liver Yang (for dizziness, irritability), stop excessive discharges (like sweating, diarrhea, seminal emission), and promote healing of sores when used topically.
• Q: Is Long Gu safe to take?
  • A: It carries potential risks, most importantly heavy metal contamination from poor sourcing. It can also cause constipation. It’s safest when prescribed by a qualified TCM practitioner who uses tested, high-quality herbs. It’s not recommended for self-treatment without professional guidance.
• Q: Is Long Gu really from dragons?
  • A: No, that’s a myth stemming from its name! It’s fossilized bone from ancient mammals like elephants and rhinos¹⁷.

The Bottom Line

Long Gu (Os Draconis) is a fascinating traditional Chinese medicine ingredient with a rich history, derived from fossilized mammalian bones. Traditionally valued for its calming, grounding, and astringent properties, some preliminary scientific research hints at plausible mechanisms for these effects, often linked to its high calcium content.  

However, the lack of robust human clinical trials and the very real risk of heavy metal contamination mean it should be approached with caution. It is not a part of mainstream medicine and should only be used under the guidance of a qualified TCM practitioner who sources high-quality, tested ingredients.

Always consult with your healthcare provider or a licensed TCM professional before starting any new herbal treatment, especially one like Long Gu, to ensure it’s appropriate and safe for you.

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