Di Long (Pheretima aspergillum) Pharmacology — The ‘Earth Dragon’ Behind Da Huo Luo Dan, Stroke-Recovery Pills, and Modern Lumbrokinase Research

If you have followed our recent deep-dives on Quan Xie (whole scorpion) and Wu Gong (centipede), you already know the story of the 搜风通络虫类药 — the “wind-searching, channel-unblocking insect drugs” that classical Chinese physicians reached for when a stubborn pain refused to yield to ordinary plant medicines. There is a third member of this family, and it is the one most likely to surprise you: Di Long (地龙), literally “earth dragon” — the dried, processed bodies of several species of large earthworm.

The name is poetic, the creature is not. Yet Di Long is arguably the most pharmacologically interesting of the three, because it is the only one whose principal active constituent — the fibrinolytic enzyme lumbrokinase (蚓激酶) — has crossed over into mainstream cardiovascular and neurological medicine. While Quan Xie and Wu Gong remain mostly within the herbal cabinet, lumbrokinase is sold as a prescription drug in China for ischemic stroke and is marketed worldwide as a nutraceutical for clot-related disorders.

This guide traces Di Long through its three lives: the classical TCM herb you find inside Da Huo Luo Dan (大活络丹) and a long list of trauma liniments; the modern pharmacological agent with documented anti-thrombotic, anti-inflammatory, anti-asthmatic, and anti-fibrotic activity; and the over-the-counter capsule that has quietly become one of the most successful TCM-derived export products of the last twenty years.

What Di Long actually is

Di Long is not a single species. The 2020 Chinese Pharmacopoeia recognises four species, divided into two commercial grades:

The processing is straightforward but sets Di Long apart from most animal drugs: live worms are slit open, the gut contents (which contain soil) are washed out thoroughly, and the body wall is dried — sometimes plain, sometimes after rinsing in saline or a vinegar wash, depending on the practitioner’s tradition and the intended use.

In TCM theory, Di Long is salty (咸) and cold (寒), entering the Liver, Spleen, Bladder, and Lung channels. Its four classical functions are:

  1. Clear heat and stop spasm (清热定惊) — for high fever with convulsions.
  2. Calm wheezing (通络平喘) — for hot-type asthma with sticky yellow sputum.
  3. Promote diuresis (利尿) — for damp-heat type dysuria.
  4. Unblock channels and collaterals (通经活络) — for hemiplegia after stroke, joint pain, and rheumatic obstruction.

It is the fourth function that lands Di Long in medicated oils and trauma pills — and the second that explains its role in respiratory formulas.

Where you find Di Long in real Chinese medicine

Unlike scorpion and centipede, which appear mostly in spasm-resolving and anti-pain formulas, Di Long has a much wider footprint. The same dried worm shows up in three very different categories of products:

Stroke and channel-unblocking pills. Di Long is a core ingredient in Da Huo Luo Dan (大活络丹), the famous “Major Invigorate the Collaterals Special Pill” containing roughly fifty herbs and animal products, indicated for sequelae of stroke (hemiplegia, slurred speech, facial paralysis), severe rheumatic joint pain, and traumatic numbness. It is also in Xiao Huo Luo Dan (小活络丹) and a long list of Republican-era and modern stroke-recovery patents like Hua Tuo Zai Zao Wan (华佗再造丸) and Bu Yang Huan Wu Tang preparations.

Joint and trauma liniments. Di Long extract or powder is added to several Lingnan-tradition 跌打油 (dieda yao you) and 风湿酒 (rheumatism wine) for its channel-opening and anti-stasis effect. It is rarely the headline ingredient — Hong Hua, Xue Jie, Ru Xiang, Mo Yao, Liang Mian Zhen and the anti-spasm trio (Quan Xie + Wu Gong + Di Long) usually share top billing — but its presence is one marker of a genuinely classical formulation rather than a simple menthol-camphor base.

Asthma and cough decoctions. Modern hospital TCM departments still prescribe Wuwei Dilong Tang (五味地龙汤) and similar combinations for hot-phase bronchial asthma, where the worm’s bronchodilatory action complements xanthine-class pharmaceuticals.

Lumbrokinase capsules. Sold under the brand names Boluoke (百奥克) in mainland China and Boluoke / Lumbrokinase capsules abroad, this purified enzyme preparation is the modern face of Di Long — a state-approved class III TCM-derived drug for ischemic cerebrovascular disease.

The chemistry: 509 compounds and one enzyme that matters most

Modern phytochemistry has isolated more than five hundred compounds from Pheretima aspergillum alone. The 2024 comprehensive review in Pharmacological Research breaks them into the following groups:

For our purposes — pain, joint, and channel-unblocking work — the relevant constituents are:

Lumbrokinase (蚓激酶, LK). A group of six closely related serine proteases, not a single enzyme. Together they have two complementary actions: direct fibrinolysis (they cleave fibrin clots themselves, the way the pharmaceutical drug streptokinase does) and indirect fibrinolysis (they upregulate tissue plasminogen activator, t-PA, so the body’s own clot-busting machinery runs faster). This dual mechanism is unusual — most thrombolytics do only one or the other — and gives lumbrokinase its reputation for breaking clots without causing the systemic bleeding seen with high-dose streptokinase.

Earthworm serine protease (ESP) and antimicrobial peptides. The peptide fraction has documented anti-inflammatory activity, suppressing TNF-α, IL-6, and NF-κB signalling in cultured cells and in carrageenan-induced paw oedema models.

Hypoxanthine and other purine nucleosides. These are the constituents responsible for the classical bronchodilator effect. Hypoxanthine and its xanthine relatives relax bronchial smooth muscle through a mechanism similar to theophylline.

Arachidonic acid and arachidonate metabolites. Present in the lipid fraction, modulating leukotriene B4 (LTB4) and interferon-γ in airway inflammation models — which is why earthworm decoctions help with hot-phase asthma.

Modern pharmacological evidence

Here is where Di Long pulls ahead of its insect-drug cousins. The peer-reviewed literature on Pheretima is genuinely large.

Antithrombotic and fibrinolytic. Lumbrokinase has been shown in vitro to dissolve fibrin clots within minutes and to prolong activated partial thromboplastin time (aPTT) and prothrombin time (PT) at clinically achievable doses. A 2024 meta-analysis in cerebrovascular research concluded that oral lumbrokinase added to standard care for acute ischemic stroke produced statistically significant improvements in neurological deficit scores with no increase in bleeding complications.

Anti-inflammatory. Earthworm extract suppresses NF-κB activation in bronchial epithelial cells and reduces TGF-β1, α-SMA, and tissue inflammatory markers in fibrosis models. This is the molecular basis for the classical “通络” (“unblock the channels”) action — channel obstruction in TCM theory often maps to chronic, low-grade tissue inflammation in modern terms.

Anti-asthmatic. Pheretima aspergillum decoction inhibits leukotriene B4, modulates IFN-γ, and reduces mucus secretion in mouse asthma models — a mechanism profile that resembles a weak leukotriene-receptor antagonist. This explains why classical physicians paired Di Long with Ma Huang for hot-phase wheezing centuries before either compound had been chemically characterised.

Antifibrotic. A 2022 systematic review and meta-analysis in Frontiers in Pharmacology aggregated thirty preclinical studies and concluded that Pheretima aspergillum significantly reduced renal, hepatic, and cardiac fibrosis markers across multiple animal models.

Bone and tendon. A 2014 study in Evidence-Based Complementary and Alternative Medicine demonstrated that Pheretima aspergillum extract stimulated osteoblast activity and inhibited osteoclast differentiation in vitro, providing a mechanism for the classical use of Di Long in bone-knitting (接骨) trauma formulations.

Wound healing. Earthworm extract accelerated the healing of deep second-degree burn wounds in a 2021 controlled clinical trial published in Annals of Palliative Medicine, with significantly faster epithelialisation than the silver sulfadiazine control.

The medicated-oil angle: what Di Long actually does on your skin

This is the part that gets glossed over in most online sources, so let us be careful. Di Long enters medicated oils in two distinct ways:

As a whole-herb component of trauma liniments. Many classical Lingnan 跌打酒 and 风湿油 are produced by macerating crude Di Long together with Hong Hua, Xue Jie, Ru Xiang, Mo Yao, and the anti-spasm trio in 50–60% rice wine for several months, then re-formulating the resulting tincture into an oil base. The transdermal absorption of large enzymes like lumbrokinase from such a preparation is essentially zero — the enzyme is too large to cross intact stratum corneum. What you do absorb is the smaller-molecular-weight fraction: free amino acids, trace elements, hypoxanthine, and the smaller anti-inflammatory peptides. The classical justification for adding Di Long to a topical is not direct enzymatic clot-busting in the local tissue but rather augmentation of the formula’s overall 通经活络 (“channel-unblocking”) character.

As a marker of formulation provenance. Practically, the presence of Di Long on the ingredient list is a useful authenticity signal. Cheap counterfeit “trauma oils” almost never include it, because crude Di Long is expensive (Guang Di Long retails for several hundred RMB per kilogram), inventory is hard to source consistently, and it adds nothing to the smell or skin sensation. A formulation that lists Di Long alongside Quan Xie, Wu Gong, and the resin trio almost always represents a more conservative, classical pharmaceutical line — typically older Hong Kong, Macau, or Vietnamese houses.

For the oral lumbrokinase capsule, the story is different — enteric coating is essential, since unprotected enzyme is destroyed by stomach acid. Properly enteric-coated capsules show measurable post-dose fibrinolytic activity in plasma; uncoated powders do not.

Safety and interactions

Di Long is one of the safer animal drugs in the materia medica. The 2020 Chinese Pharmacopoeia lists no toxic constituents and assigns it the standard 4.5–9 g daily oral dose. There is no chronic toxicity signal in the published literature, and the LD50 in rodents is high enough that it is essentially impossible to overdose on a normal-size human via oral routes.

That said, two real interactions deserve attention:

Anticoagulants and antiplatelet drugs. Because lumbrokinase has documented antithrombotic activity, oral Di Long preparations — and especially purified lumbrokinase capsules — should not be combined with warfarin, direct oral anticoagulants (apixaban, rivaroxaban, dabigatran), heparin, aspirin, or clopidogrel without medical supervision. The interaction is pharmacologically additive and the bleeding risk is real. This caution does not meaningfully extend to topical medicated oils, where systemic absorption of intact enzyme is negligible — but if you are on blood thinners and using a Di Long-containing liniment over very large areas of broken skin, mention it to your physician.

Pregnancy. Classical TCM lists Di Long as 慎用 (“use with caution”) in pregnancy because of its blood-moving and channel-unblocking action. There are no controlled human studies. The conservative position is to avoid both oral and topical Di Long-containing products during pregnancy.

Allergy. Earthworm proteins are a recognised though uncommon cause of contact urticaria in fishermen and bait-shop workers chronically exposed to live worms. Allergic reactions to processed Di Long in oral preparations are very rare but documented; topical reactions to liniments containing whole-herb Di Long are likewise possible but unusual.

How Di Long fits beside its insect cousins

If you read our Quan Xie and Wu Gong articles, the comparative picture is now clear:

Together the three form a pharmacological tripod that classical formulators reached for again and again — not because they liked exotic ingredients, but because each one addressed a different downstream pathway of the same upstream problem: tissue and fluid that has stopped moving the way it should.

What to look for on a label

If you are evaluating a trauma oil or rheumatism wine and you see “Di Long (地龙)” on the ingredient list, that is generally a positive signal — it suggests a more classical, conservative formulation. The presence of all three insects (Quan Xie, Wu Gong, Di Long) together with the resin pair (Ru Xiang, Mo Yao) and at least one of the blood-mover plants (Hong Hua, Xue Jie, San Qi) is the signature of a serious channel-unblocking formula.

For oral lumbrokinase specifically, look for the words “enteric-coated (肠溶)” and a stated activity unit (typically expressed in IU per capsule or fibrinolytic units per dose). Capsules without enteric coating are essentially expensive earthworm flour.

The earth dragon may be the least glamorous member of the 搜风通络 trio, but it has aged better than either of its more dramatic cousins. While Quan Xie and Wu Gong remain firmly inside the herbal cabinet, Di Long has quietly become the only one of the three whose active principle is reaching for a place in the modern cardiovascular pharmacopoeia. That is a remarkable second act for a humble earthworm.

Sources & further reading

This article is for educational reference only and does not constitute medical advice. Consult a licensed practitioner before using earthworm-containing preparations, particularly if you take anticoagulants or are pregnant.