Shui Zhi
StarWhitmania pigra Whitman, Hirudo nipponica Whitman, Whitmania acranulata Whitman
Traditionally used for
- Digestion
- Menstrual & women's health
Cautions & contraindications
- Pregnancy
- Bleeding disorders
- Before surgery
- Toxic — professional use only
☯ TCM Properties
Breaks Blood and Dispels Stasis; Promotes Menstruation; Disperses Accumulations and Dissipates Nodules
Traditional Chinese Uses
Shui Zhi (leech) is one of the most powerful Blood-stasis-breaking substances in the Chinese materia medica, reserved for deep, stubborn, long-standing Blood stagnation that resists gentler herbs. This includes fixed abdominal masses, absent menstruation from Blood clots obstructing the uterus, traumatic injuries with severe internal bruising, and the aftermath of stroke. Classical sources note it disperses old stagnant Blood while preserving newly generated healthy Blood.
Relationships
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Botanical Description
Shui Zhi is the dried whole body of medicinal leeches, principally Whitmania pigra Whitman, Hirudo nipponica Whitman, or Whitmania acranulata Whitman (Hirudinidae), aquatic segmented annelids found in freshwater ponds, ditches, and rice paddies across East Asia. The animals are collected in summer and autumn, killed in hot water or lime, then dried whole and cut into pieces before use. Leech bodies contain hirudin, a potent antithrombin peptide, along with histamine-like vasodilators, hyaluronidase, and other bioactive proteins concentrated in the salivary glands. In traditional Chinese medicine, Shui Zhi is salty, bitter, and neutral with mild toxicity, entering the liver channel; it strongly invigorates the blood and breaks up blood stasis, used for amenorrhea from blood stasis, abdominal masses, traumatic injury, and post-stroke hemiplegia. It is contraindicated in pregnancy and in patients without true blood stasis.
Active Constituents
Hirudin
Polypeptide direct thrombin inhibitor (about 7 kDa, 65 amino acids)Concentration: present in fresh salivary tissue of the hematophagous Hirudo nipponica; not detected in dried and processed commercial drug
The compound the reputation of this drug rests on, and the one most often misdescribed. Hirudin is a potent direct thrombin inhibitor, but three facts constrain what it can do in a decoction. First, it is a salivary product of blood-feeding leeches; the Chinese Pharmacopoeia accordingly sets a much higher antithrombin potency limit for Hirudo nipponica, at not less than 16.0 units per gram, than for Whitmania pigra and Whitmania acranulata, at not less than 3.0 units per gram, and one quality study measured roughly a fifty-fold difference in thrombin consumption between Hirudo nipponica and Whitmania pigra samples. Second, the older claim that Whitmania contains no hirudin at all is now known to be too simple: several hirudin-encoding sequences from Whitmania pigra were cloned and expressed in 2022 and some of the recombinant proteins were genuine thrombin inhibitors, while others were hirudin-like factors with little or no thrombin-inhibitory activity. Third, and decisive for practice, hirudin is heat-labile and was not detected at all in processed commercial leech samples, and as a 65-residue polypeptide it is digested rather than absorbed when swallowed. Whatever the decocted drug does, it is not doing it through intact circulating hirudin.
Whitide
Anticoagulant oligopeptide (1997.1 Da, collagen-homologous)Concentration: isolated from Whitmania pigra; no routine content specification
A 22-residue hydroxyproline-rich oligopeptide purified from Whitmania pigra with anticoagulant activity, whose sequence has strong homology to collagen. Unlike hirudin it is stable to heat and to trypsin, which is why its discoverers proposed it as a plausible orally active anticoagulant principle of the drug. This, and the related small peptides, are a far better candidate for what a decoction actually delivers than hirudin is.
Pteridine derivatives (hirudonucleodisulfides A and B, hirudinoidines A to C, pteridinediones)
PteridineSmall-molecule markers used to distinguish the pharmacopoeial species chemically: the hirudonucleodisulfides and related pteridinediones are reported from Whitmania pigra, the hirudinoidines from Hirudo nipponica. They are analytically useful for species authentication even where the macromolecular fraction has been destroyed by drying.
Hypoxanthine, xanthine, uracil and uridine
Purine and pyrimidine nucleoside/nucleobaseSmall nitrogenous molecules common to all three official species. They survive drying and decoction and are used as chromatographic markers, but no anticoagulant activity is attributed to them.
Antithrombotic proteins other than hirudin (coagulation inhibitors, platelet aggregation inhibitors, fibrinolysis enhancers)
Protein and peptide antithrombotic familiesGenome sequencing of Whitmania pigra identified 79 antithrombotic genes across twenty families, comprising thirteen coagulation inhibitor families, three platelet aggregation inhibitor families, three fibrinolysis enhancer families and one tissue penetration enhancer, which is more than the 72 found in the blood-feeding Hirudinaria manillensis. The finding undercuts the assumption that a non-blood-feeding leech must be pharmacologically weaker across the board, even though its antithrombin potency specification is lower. Most of these are large proteins with the same oral bioavailability problem as hirudin.
⚠ Drug Interactions
Warfarin, direct oral anticoagulants and heparins
This is where species matters more than for almost any other drug in the materia medica. The Chinese Pharmacopoeia potency limit for Hirudo nipponica is more than five times that for the two Whitmania species, and a quality-evaluation study measured roughly a fifty-fold difference in thrombin consumption between Hirudo nipponica and Whitmania pigra samples, so a decoction of one species is not pharmacologically equivalent to the same weight of another. Against that, the anticoagulant contribution of intact hirudin in an oral preparation is negligible: hirudin is heat-labile and was undetectable in processed samples, and a 65-residue polypeptide is not absorbed intact from the gut. The realistic mechanism for an oral interaction is the small heat- and trypsin-stable peptides such as whitide together with the small-molecule fraction, and raw and talcum-processed Whitmania pigra both produced measurable antithrombotic effects in mice. Treat the interaction as real but of uncertain magnitude rather than as an additive dose of a direct thrombin inhibitor.
Clinical note: Do not combine with an anticoagulant without monitoring, and record which species was dispensed. If a patient on warfarin starts Shui Zhi, check INR at one and two weeks. Insist on a certificate of analysis that names the species and reports antithrombin units per gram, since the two Whitmania species and Hirudo nipponica are dispensed interchangeably under one pinyin name but are not interchangeable in potency.
Aspirin, clopidogrel and other antiplatelet drugs
Whitmania pigra expresses three families of platelet aggregation inhibitor genes alongside its coagulation inhibitors, and raw and processed leech preparations were antithrombotic in mouse models. No human study has measured platelet function on oral leech preparations, so the interaction is extrapolated from animal and genomic data.
Clinical note: Avoid stacking on dual antiplatelet therapy. Withhold before surgery, dental extraction and neuraxial procedures, and ask specifically about epistaxis, gum bleeding and menorrhagia.
Recombinant hirudin products (lepirudin, desirudin, bivalirudin)
Named here to correct a common inference rather than to assert a hazard. Because leech is described as containing hirudin, practitioners sometimes reason that oral Shui Zhi behaves like a parenteral direct thrombin inhibitor. It does not: hirudin was not detectable in processed commercial leech material, it is destroyed by the heat of drying and decoction, and as a polypeptide it is digested rather than absorbed. The parenteral hirudin analogues are given intravenously precisely because the oral route does not work. Any additive effect from combining them would come from the herb's small peptides, not from herbal hirudin.
Clinical note: In a patient anticoagulated with a parenteral direct thrombin inhibitor, stop the herb, as you would any stasis-breaking herb, but do not attribute a potency to it that the oral route cannot deliver.
Use in pregnancy, with or without concomitant drugs
Shui Zhi is classed among the drugs contraindicated in pregnancy in the Chinese Pharmacopoeia and throughout the classical literature, on the basis of its strong Blood-breaking action and reported abortifacient effect. It is also recorded as slightly toxic, with overdose producing nausea, vomiting, abdominal pain, gastrointestinal haemorrhage, haematuria, metrorrhagia and, in severe cases, coma within one to four hours.
Clinical note: Absolute contraindication in pregnancy and in women attempting conception. Avoid in active peptic ulcer, thrombocytopenia, haemophilia and any recent haemorrhagic stroke, and do not exceed the pharmacopoeial dose range.
Poecilobdella manillensis (Hirudinaria manillensis) supplied as Shui Zhi
Poecilobdella manillensis is a blood-feeding leech used in Guangxi Zhuang medicine and is not one of the three species listed in the Chinese Pharmacopoeia entry for Hirudo, but it appears in the medicinal leech supply. Its antithrombin activity was measured at 173.1 units in a comparative quality study, far exceeding Whitmania pigra and comparable with or above Hirudo nipponica; one report puts its anticoagulant activity around twenty times that of the non-hematophagous Whitmania pigra. Substituting it for Whitmania therefore substitutes a much more potent anticoagulant material at the same weight.
Clinical note: Where a leech product is dispensed to an anticoagulated patient, verify the binomial rather than accepting Hirudo or Shui Zhi on the label. A change of supplier can change the effective potency several-fold with no change in the prescribed dose.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction | 1–3 g | Daily | — | — | 中国药典 2020 【用法与用量】1～3g。 【注意】孕妇禁用。 【性味与归经】咸、苦，平；有小毒。归肝经。 — Chinese Pharmacopoeia 2020, quoted verbatim; route and cautions preserved. Replaces a cleared category-filler value. |
Dui Yao — Herb Pairs
The classical two-herb combinations this herb appears in, each with an action neither herb has alone.
The combination of two insect medicinals breaks severe, entrenched blood stasis far more forcefully than plant blood-movers.
Blood amassment in the lower burner with lower abdominal hardness and mania; very harsh, contraindicated in pregnancy and in bleeding or deficiency.
Core pair of a classical formula — Di Dang Tang, Shang Han Lun (Zhang Zhongjing)
Evidence Tier
Moderate evidence · 5 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
0
Randomized controlled trial
0
Other clinical trial
0
Observational / case report
0
In vitro / animal
5
1 verified · 4 unverified
Show 5 studies
- Life without blood: Molecular and functional analysis of hirudins and hirudin‐like factors of the Asian non‐hematophagous leech Whitmania pigra
- A Comprehensive Quality Evaluation System for Medicinal Leeches by Integrating Macromolecular Protein Analysis and Small-Molecule Marker Detection as Well as Quantitative Bioassays
- Purification and characterization of an anticoagulant oligopeptide from Whitmania pigra Whitman
- Antithrombotic pharmacodynamics and metabolomics study in raw and processed products of Whitmania pigra Whitman
- A Chromosome-Level Genome Assembly of the Non-Hematophagous Leech Whitmania pigra (Whitman 1884): Identification and Expression Analysis of Antithrombotic Genes
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
Life without blood: Molecular and functional analysis of hirudins and hirudin‐like factors of the Asian non‐hematophagous leech Whitmania pigra
The study that settles whether the non-blood-feeding Whitmania pigra makes hirudin. Putative hirudin-encoding sequences were identified in Whitmania pigra transcriptome data, synthesised, expressed in E. coli, purified and assayed for thrombin inhibition. Some, but not all, were genuine thrombin inhibitors: Whitmania pigra expresses both true hirudins and hirudin-like factors that inhibit thrombin weakly or not at all. Some of the same coding sequences were also present in transcriptome data of the blood-feeding Hirudo nipponica. This is the first description of hirudins in a non-hematophagous leech and it corrects the widespread claim that hirudin is confined to Hirudo.
A Comprehensive Quality Evaluation System for Medicinal Leeches by Integrating Macromolecular Protein Analysis and Small-Molecule Marker Detection as Well as Quantitative Bioassays
Commercial medicinal leech samples were evaluated by protein profiling, small-molecule markers and quantitative antithrombin bioassay. Thrombin consumed by Hirudo nipponica samples exceeded that consumed by Whitmania pigra samples by roughly fifty-fold on average, consistent with the Chinese Pharmacopoeia limits of not less than 16.0 units per gram for Hirudo nipponica against not less than 3.0 units per gram for Whitmania pigra; Poecilobdella manillensis measured 173.1 units. Critically, the 7 kDa hirudin band was not detected in the tested samples at all, which the authors attribute to its heat-lability during the traditional drying and processing of the drug.
Purification and characterization of an anticoagulant oligopeptide from Whitmania pigra Whitman
An anticoagulant oligopeptide, named whitide, was purified from dried Whitmania pigra by gel filtration, ion exchange and preparative HPLC. Its molecular weight is 1997.1 Da and its 22-residue hydroxyproline-rich sequence shows strong homology to collagen. Because it is stable to heat and to trypsin, the authors propose it as an orally viable anticoagulant principle, in explicit contrast to hirudin. This is the most direct published answer to what a decoction of the drug can actually deliver.
Antithrombotic pharmacodynamics and metabolomics study in raw and processed products of Whitmania pigra Whitman
Both raw and talcum-powder-processed Whitmania pigra were antithrombotic in mice, with the processed product showing the more apparent effect, so the traditional high-temperature processing does not abolish activity. Fifty-eight differential metabolites were identified, with changes concentrated in sphingolipid and glycerophospholipid metabolism. The authors suggest protein denaturation during processing may increase peptide availability, which is consistent with the activity residing in small peptides rather than in intact hirudin.
A Chromosome-Level Genome Assembly of the Non-Hematophagous Leech Whitmania pigra (Whitman 1884): Identification and Expression Analysis of Antithrombotic Genes
A chromosome-level genome of Whitmania pigra identified 79 antithrombotic genes in twenty families, comprising thirteen coagulation inhibitors, three platelet aggregation inhibitors, three fibrinolysis enhancers and one tissue penetration enhancer, exceeding the 72 found in the blood-feeding Hirudinaria manillensis. Expression comparison against Hirudinaria manillensis showed five families expressed significantly higher and four significantly lower in Whitmania pigra. The authors conclude that a non-hematophagous leech is not necessarily poorer in antithrombotic biomacromolecules than a blood-feeding one.
⚠ Safety & Contraindications
- Pregnancy
- Bleeding disorders
- Before surgery
- Toxic — professional use only
Contraindications
Contraindicated in pregnancy, in any bleeding disorder, in active bleeding, and in patients on anticoagulants.
Safety Warnings
- Anticoagulant. Additive bleeding risk with warfarin, heparin, direct oral anticoagulants, aspirin and other antiplatelet drugs.
- Stop well before surgery.
⚠ Rule-Based Cautions
These entries come from the deterministic rule tables that gate Verscienta's formula tools — classical pair prohibitions, pregnancy and lactation contraindications, and dose ceilings.
Pregnancy
Avoid blood-breaker
⚠ Toxicity Information
Bleeding and prolonged clotting are the effect of concern rather than classical poisoning; allergic reaction is reported.
Historical Texts
Shen Nong Ben Cao Jing
Han dynasty, compiled by the 2nd centuryShang Han Lun and Jin Gui Yao Lue
Eastern Han dynasty, c. 200-220 CEBen Cao Gang Mu
Ming dynasty, 1578References
- Dong Han, Ren Ji-Xiang, Wang Jing-Jing, Ding Li-Shuai, Zhao Jian-Jun, Liu Song-Yan, Gao Hui-Min. Chinese Medicinal Leech: Ethnopharmacology, Phytochemistry, and Pharmacological Activities . Evidence-Based Complementary and Alternative Medicine (2016) [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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