Zhu Dan
StarSus scrofa domestica Brisson
Traditionally used for
- Eye health
- Nose & throat
- Cough & breathing
- Bowel health
Cautions & contraindications
- Liver conditions
☯ TCM Properties
Clears Heat; Moistens Dryness; Resolves Toxicity; Stops Cough and Calms Wheezing; Moistens the Intestines and Unblocks the Bowels
Traditional Chinese Uses
Zhu Dan (pig bile) is a cold, bitter substance that clears internal Heat, moistens intestinal dryness, and resolves toxins. In Chinese medicine it is most recognized for addressing constipation from fluid depletion, chronic cough and wheezing from heat-dryness, sore throat, and red, inflamed eyes. Its historical significance is notable — Zhang Zhongjing's Shang Han Lun employed it both as a rectal enema for constipation and as an emergency ingredient for severe Yang-collapse conditions.
Relationships
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Botanical Description
Zhu Dan is the dried bile or gallbladder of the domestic pig, Sus scrofa domestica L. (Suidae), obtained as a byproduct of slaughter. The fresh bile, a viscous green-yellow fluid stored in the gallbladder, is collected and either concentrated by evaporation to a dark brown extract (Zhu Dan Zhi) or the entire bile-filled gallbladder is dried whole. The substance contains conjugated bile acids (notably hyodeoxycholic and chenodeoxycholic acid), bile pigments (bilirubin, biliverdin), cholesterol, and phospholipids responsible for emulsifying fats and modulating intestinal flora. In traditional Chinese medicine, Zhu Dan is bitter, cold, and slightly toxic, entering the liver, gallbladder, lung, and large intestine channels; it clears heat, moistens dryness, resolves toxicity, transforms phlegm, and stops cough, used for cough with thick yellow phlegm, constipation from heat dryness, eye redness, jaundice, and topically for skin sores. It is an ingredient in classical formulas such as Dan Dao Pai Shi Tang and historically used to coat pills (Zhu Dan Zhi Wan).
Active Constituents
Hyodeoxycholic acid (HDCA)
Secondary bile acid (3alpha,6alpha-dihydroxy-5beta-cholan-24-oic acid)Concentration: the dominant bile acid of pig bile, reported at roughly 68-71% of the total bile acid fraction
The single constituent that defines pig bile chemically. It is a 6alpha-hydroxylated bile acid that other common mammals do not make in quantity, and its presence is the analytical basis for identifying this drug and excluding substitution with bile of another species. Pharmacologically it is a choleretic; the 2023 Chinese Pharmacopoeia lists hyodeoxycholic acid as a choleretic drug raw material and the European Medicines Agency granted it orphan designation for gallstone dissolution in 2022. It also improves glucose homeostasis by promoting GLP-1 secretion from intestinal L cells.
Hyocholic acid (HCA)
Primary bile acid (3alpha,6alpha,7alpha-trihydroxy-5beta-cholan-24-oic acid)Concentration: around 8% of pig bile acids as the free acid, but hyocholic acid species together account for more than 70% of the total pig bile acid pool
The characteristic primary bile acid of the pig and the other marker that distinguishes this drug from bovine, ovine and ursine bile. Hyocholic acid species are inversely associated with diabetes and glycaemic markers in human cohorts, and they are the constituents behind the GLP-1 and glucose effects of pig bile powder.
Chenodeoxycholic acid (CDCA)
Primary bile acid (3alpha,7alpha-dihydroxy-5beta-cholan-24-oic acid)Concentration: roughly 19-20% of pig bile acids
A bile acid shared with humans and a licensed drug in its own right for cholesterol gallstone dissolution and for cerebrotendinous xanthomatosis. It is also the most potent natural agonist of the farnesoid X receptor, which is relevant because the net FXR effect of the whole drug is inhibitory rather than agonist.
Taurohyodeoxycholic acid (THDCA)
Taurine-conjugated bile acidConcentration: the official assay marker for pig bile powder; the Chinese Pharmacopoeia requires not less than 2% total THDCA in medicinal-grade material
The taurine conjugate of the drug's principal bile acid and the constituent against which commercial pig bile powder is standardised. Conjugation keeps the bile acid ionised and detergent-active through the small intestine, which is what allows it to reach the ileal and colonic receptors that mediate the GLP-1 effect.
Glycohyodeoxycholic acid (GHDCA)
Glycine-conjugated bile acidThe glycine conjugate that accompanies THDCA in pig bile. Glycine and taurine conjugates of chenodeoxycholic, hyodeoxycholic, hyocholic and cholic acid are the forms actually present in freshly collected bile; free acids in a dried powder largely reflect deconjugation during collection and processing.
Cholic acid
Primary bile acid (trihydroxy)Present as glycine and taurine conjugates but a minor component of pig bile relative to the hyo- series. Its low share is itself diagnostic, since bovine bile is cholic-acid dominated.
Bilirubin and biliverdin
Tetrapyrrole bile pigmentsThe pigments that give the drug its colour, present alongside proteins and lipids in the non-bile-acid fraction. They are not the active fraction; bile acids are, at roughly 83% of the powder in the material used in the diabetes work.
⚠ Drug Interactions
Xiong Dan / Fel Ursi (bear bile), for which pig bile is a documented substitute
Pig bile is the cheapest of the animal bile drugs and bear bile the most expensive, and the two are interchanged in trade. They are not equivalent: bear bile is defined by tauroursodeoxycholic acid, which pig bile does not supply, while pig bile is defined by hyodeoxycholic and hyocholic acids, which bear bile does not. LC-MS/MS bile acid profiling was developed specifically to tell the various animal-bile and gallstone drugs apart for this reason. The substitution also runs the other way in a legal sense: bear bile comes from Ursus thibetanus and Ursus arctos, which are CITES-listed, so material presented as bear bile is subject to trade prohibition in most jurisdictions and material presented as pig bile may in principle conceal it.
Clinical note: Do not accept pig bile as a substitute for bear bile in a prescription written for bear bile, or the reverse; the bile acid delivered is different. Require bile acid profile documentation for any animal bile drug. Prescribing or importing bear bile is illegal in many jurisdictions regardless of the clinical indication.
Insulin, GLP-1 receptor agonists, DPP-4 inhibitors, sulfonylureas and other glucose-lowering drugs
Pig bile powder at 25-75 mg/kg/day for 45 days reduced hyperglycaemia and improved insulin sensitivity and glucose tolerance in diabetic mice. The mechanism is inhibition of intestinal farnesoid X receptor signalling, which increases glucagon-like peptide-1 secretion from enteroendocrine L cells and thereby enhances glucose-dependent insulin secretion. Because that is the same endogenous hormone a GLP-1 agonist or a DPP-4 inhibitor is designed to amplify, the pathways converge rather than acting independently. The evidence is animal and cellular; no human study has been done.
Clinical note: Advise glucose monitoring if pig bile powder is used at material doses in a patient on incretin-based or insulin therapy, and be alert to additive gastrointestinal effects, since both GLP-1 agonists and bile acids slow gastric emptying and loosen stool.
Obeticholic acid and other FXR agonists
The demonstrated intestinal action of pig bile powder is inhibition of farnesoid X receptor signalling. Obeticholic acid is a semisynthetic FXR agonist. The two therefore act in opposite directions at the same receptor, so concurrent use would be expected to blunt the drug. This is an inference from the established mechanism of each, not an interaction that has been measured.
Clinical note: Avoid concurrent use with a prescribed FXR agonist unless there is a specific reason, and do not assume the herb is inert in a patient being treated for cholestatic liver disease.
Bile acid sequestrants (cholestyramine, colestipol, colesevelam) and orlistat
The active fraction of this drug is bile acids, and bile acid sequestrants are anion-exchange resins whose entire purpose is to bind bile acids in the gut lumen and prevent their reabsorption. Given together, the sequestrant would be expected to bind the ingested bile acids and abolish the herb's intestinal FXR and GLP-1 effects, while the added bile acid load could partly consume the resin's binding capacity. Orlistat, which alters luminal fat and bile acid handling, poses a similar though weaker problem. This follows from the pharmacology of both agents; it has not been measured.
Clinical note: Separate dosing by at least four hours if both are genuinely required, and expect the herb to be ineffective in a patient on a full sequestrant dose.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| taken | 0.15–0.3 g | Daily | — | — | Standard oral dose per Xi S, Gong Y. Essentials of Chinese Materia Medica and Medical Formulas. Academic Press/Elsevier, 2017, p. 44. Exact wording: Normally, 0.15–0.3 g is taken infused as an oral |
Evidence Tier
Limited 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
0
Randomized controlled trial
0
Other clinical trial
0
Observational / case report
0
In vitro / animal
2
0 verified · 2 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
Pig bile powder maintains blood glucose homeostasis by promoting glucagon-like peptide-1 secretion via inhibiting farnesoid X receptor
Pig bile powder, of which bile acids made up about 83% (dominated by hyocholic acid species at 51.1% and chenodeoxycholic acid species at 27.9%), was given to diabetic mice at 25-75 mg/kg/day for 45 days. It significantly reduced hyperglycaemia and improved insulin sensitivity and glucose tolerance, and long-term preventive administration protected against glucose dysregulation. The mechanism was traced to suppression of intestinal farnesoid X receptor signalling, which raised glucagon-like peptide-1 secretion from enteroendocrine L cells and thereby improved glucose-dependent insulin secretion. This is the pharmacological basis for the classical use of Zhu Dan in xiao ke, heat and thirst.
Toxicological evaluation of porcine bile powder in Kunming mice and Sprague–Dawley rats
A full regulatory toxicology package on porcine bile powder. A single 15 g/kg oral dose in mice produced no poisoning signs and no deaths over 14 days, giving an LD50 above 15 g/kg. In a 90-day repeat-dose study, rats given 0.75, 1.50 or 2.25 g/kg/day showed no behavioural, dietary, weight or pathological change, and no differences in haematology, biochemistry, coagulation or urinalysis; organ weights and histology of liver, kidney, spleen, adrenal, brain, heart, thymus and reproductive organs were unaffected, giving a NOAEL at the highest dose tested. Ames, micronucleus and chromosomal aberration tests were negative and teratogenicity testing showed no abnormal fetal development. The drug is accordingly of low intrinsic toxicity; the practical risks attached to it are microbiological and identity-related rather than toxicological.
⚠ Safety & Contraindications
- Liver conditions
Contraindications
Its use is cautious in patients with deficiency-cold of the spleen and stomach.
Source: Xi S, Gong Y. Essentials of Chinese Materia Medica and Medical Formulas. Academic Press/Elsevier, 2017, p. 44.
Historical Texts
Ming Yi Bie Lu
Han to Wei periodShang Han Lun
Han dynastyReferences
- Qiao Xue, Ye Min, Pan De-lin, Miao Wen-juan, Xiang Cheng, Han Jian, Guo De-an. Differentiation of various traditional Chinese medicines derived from animal bile and gallstone: Simultaneous determination of bile acids by liquid chromatography coupled with triple quadrupole mass spectrometry . Journal of Chromatography A (2011) [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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