Huang Bai
StarPhellodendron chinense C.K.Schneid.
Traditionally used for
- Digestion
- Bowel health
- Urinary & fluids
- Menstrual & women's health
- Pain & joints
- Skin
Cautions & contraindications
- Young children
- Kidney conditions
☯ TCM Properties
Drains Damp-Heat especially from the Lower Jiao; Drains Kidney Fire (False Heat, Deficiency Heat); Drains Fire and relieves Fire toxicity
Traditional Chinese Uses
Huang Bai is the dried bark of Phellodendron chinense (or P. amurense, Rutaceae), a classic bitter, cold heat-clearing/Damp-Heat-drying herb entering the Kidney, Bladder and Large Intestine channels. Its hallmark is draining Damp-Heat from the Lower Jiao: thick yellow vaginal discharge, damp genital itching and sores, Damp-Heat diarrhea and dysentery, turbid painful urination, and hot, swollen, weak knees and legs (as in Er Miao San with Cang Zhu). It drains Kidney Fire and Deficiency-Heat with steaming bones, night sweats and nocturnal emission, classically paired with Zhi Mu and Yin tonics in Zhi Bai Di Huang Wan.
It also drains Fire and relieves Fire-toxicity in hot sores, abscesses and eczema, applied internally or topically. Being cold and bitter, it is used cautiously in Spleen/Stomach deficiency and Cold patterns.
Western Herbalism Properties
Used In Formulas (7)
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
Huang Bai is the dried inner bark of Phellodendron chinense C.K.Schneid. or Phellodendron amurense Rupr. (Rutaceae), commonly called Chinese or Amur cork tree. The parent tree is a medium to large deciduous tree 10-25 m tall, with a broad rounded crown and a distinctive thick, deeply furrowed, soft and corky outer bark whose inner layer is brilliant yellow due to high berberine content. Opposite, odd-pinnately compound leaves bear 5-13 ovate-lanceolate leaflets, 5-10 cm long, finely toothed, and emit a pungent citrus-like odor when crushed. Dioecious panicles of small greenish-yellow flowers yield clusters of pea-sized black drupes that persist into winter. The harvested inner bark is intensely bitter and yellow, and supplies the major TCM herb for clearing damp-heat from the lower jiao, used in jaundice, leukorrhea, dysentery, and inflammatory skin conditions. Phellodendron amurense is now listed as endangered in parts of its range.
Active Constituents
Berberine
Protoberberine isoquinoline alkaloidConcentration: the Chinese Pharmacopoeia standard for Phellodendri Chinensis Cortex is not less than 3.0 percent berberine hydrochloride in the dried bark
The dominant alkaloid of this species and the compound that carries almost all of the documented pharmacology and essentially all of the documented human drug interactions of the drug. Oral absorption is very poor, so systemic effects at herbal doses are modest while gut-level antimicrobial and transporter effects are not.
Phellodendrine
Quaternary tetrahydroprotoberberine alkaloidConcentration: the Chinese Pharmacopoeia standard for Phellodendri Chinensis Cortex is not less than 0.34 percent phellodendrine hydrochloride
Genus-specific, and for that reason it is the second pharmacopoeial assay marker for the Chinese species. Because berberine also occurs in Coptis, Berberis and Mahonia, phellodendrine rather than berberine is what confirms that a sample is genuinely Phellodendron.
Palmatine
Protoberberine isoquinoline alkaloidA close structural analogue of berberine present as a secondary alkaloid. It is not the assay marker for the Chinese species, but it is the pharmacopoeial marker for the Amur species, which is one of the practical ways the two barks are told apart.
Jatrorrhizine
Protoberberine isoquinoline alkaloidA demethylated protoberberine that occurs alongside berberine and palmatine and contributes to the total quaternary alkaloid load of the bark.
Magnoflorine
Quaternary aporphine alkaloidPresent in both Phellodendron species but proportionally much more prominent in the Amur species, where it has been proposed as a quality marker. It has been reported to increase tissue uptake of berberine when the two are given together.
Obacunone
Limonoid (degraded triterpenoid)One of the bitter limonoids of the bark, along with obaculactone (limonin). These non-alkaloid constituents are part of what distinguishes Phellodendron bark chemically from the other berberine-bearing crude drugs.
⚠ Drug Interactions
Ciclosporin (cyclosporin A)
This is one of the few herb-drug interactions in this area documented directly in patients rather than inferred. In a controlled study in renal transplant recipients, berberine 0.2 g three times daily raised ciclosporin trough concentrations by 88.9 percent and the concentration/dose ratio by 98.4 percent against baseline; in the pharmacokinetic substudy, twelve days of the same berberine regimen increased ciclosporin AUC by 34.5 percent and cut apparent oral clearance by 40.4 percent. The authors attributed it to inhibition of CYP3A4 in liver and small intestine, and berberine also inhibits intestinal P-glycoprotein, which carries ciclosporin. Berberine is the principal alkaloid of this bark, so the interaction should be assumed for the crude drug.
Clinical note: Do not add Huang Bai to a stable transplant or autoimmune regimen containing ciclosporin without arranging trough monitoring first, and treat any change in the herbal prescription as a reason to re-check levels.
CYP3A4 substrates (e.g. midazolam, tacrolimus, simvastatin)
In healthy volunteers given berberine 300 mg three times daily for two weeks against probe substrates, berberine inhibited CYP3A4 activity as well as CYP2D6 and CYP2C9. The rat work of Qiu and colleagues, which showed increased exposure to CYP3A and P-glycoprotein substrates after berberine, points the same way. The size of the effect from a herbal decoction of the bark has not been measured directly, so this is graded below the ciclosporin evidence.
Clinical note: Treat as a real interaction for narrow-therapeutic-index CYP3A4 substrates; for wide-margin drugs, note it and monitor for exaggerated effect rather than avoiding the herb.
CYP2D6 and CYP2C9 substrates (e.g. dextromethorphan, metoprolol, losartan)
The same human repeated-dose study found that berberine inhibited CYP2D6 and CYP2C9 in addition to CYP3A4. CYP2D6 is polymorphic, so the practical consequence is largest in extensive metabolisers taking a drug whose activity depends on that route.
Clinical note: Ask specifically about beta-blockers, antidepressants, antipsychotics and sartans before prescribing this herb long term, and review for signs of over-treatment rather than assuming the herb is inert.
P-glycoprotein substrates (e.g. digoxin)
Berberine inhibits intestinal P-glycoprotein. In rats, gavage with berberine 100 mg/kg for two weeks raised the AUC of digoxin by about 69 percent. This has not been reproduced in humans, and it is a rat dose, so the human relevance is inferred rather than measured.
Clinical note: For digoxin specifically, the margin is small enough that the possibility is worth a level check if the herb is used for more than a few days.
Neonatal use and any drug or condition raising unconjugated bilirubin
Berberine displaces bilirubin from serum albumin. In vitro it was roughly tenfold more potent as a displacer than phenylbutazone and about a hundredfold more potent than papaverine, and chronic dosing in rats significantly reduced bilirubin protein binding with a persistent rise in unbound and total serum bilirubin. This is a genuine mechanistic contraindication, not a precaution: Singapore has restricted berberine-containing Coptis and Phellodendron since 1978 on exactly this basis. The published clinical evidence linking the herbs themselves to kernicterus is contested, but the displacement chemistry is not.
Clinical note: Do not give this herb to neonates, to jaundiced infants, or to a woman in the peripartum period where the alkaloid may reach the newborn through the placenta or breast milk. Say so explicitly rather than listing it as a caution.
Glucose-6-phosphate dehydrogenase deficiency and oxidant drugs in haemolysis-prone patients
The historical allegation is that berberine-containing Coptis and Phellodendron aggravate haemolysis in G6PD-deficient patients. A clinical re-examination of the question in patients with chronic haematological disease found the evidence for berberine-induced haemolysis to be weaker than the ban implies, but recommended bilirubin and haemoglobin monitoring where an underlying haemolytic disease exists. So the risk is real enough to monitor and not strong enough to prohibit in adults.
Clinical note: In a patient with known G6PD deficiency, thalassaemia or another chronic haemolytic disorder, check haemoglobin and bilirubin before and during a course rather than refusing the herb outright.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction | 3–12 g | Daily | — | — | 中国药典 2020 monograph 【黄柏】【用法与用量】3～12g。外用适量。 【性味与归经】苦，寒。归肾、膀胱经。 — Matched to ChP by romanised drug name (pinyin 'Huang Bai' → 黄柏); the romanisation is unique across all 649 ChP monographs, and the match was cross-checked against this record's own TCM temperature. Quoted verbatim. |
Dui Yao — Herb Pairs
The classical two-herb combinations this herb appears in, each with an action neither herb has alone.
Together they clear heat and dry damp in the lower burner, treating damp-heat descending to the legs.
Classic indication: hot, swollen, painful legs and knees, or damp-heat leukorrhea.
Core pair of a classical formula — Er Miao San, Dan Xi Xin Fa (Zhu Danxi)
Together they drain Kidney fire and nourish yin, treating steaming bone fever, night sweats and deficiency-fire signs.
The pair is the core addition in Zhi Bai Di Huang Wan and appears in Da Bu Yin Wan.
Named pairing — Lu Jingshan, Shi Jinmo Dui Yao
Clearing heat through the three burners is combined with clearing damp-heat from the lower burner, treating damp-heat jaundice with heat predominant.
Core pair of a classical formula — Zhi Zi Bai Pi Tang, Shang Han Lun (Zhang Zhongjing)
Evidence Tier
Moderate evidence · 7 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
2
2 verified · 0 unverified
Other clinical trial
1
1 verified · 0 unverified
Observational / case report
0
In vitro / animal
4
0 verified · 4 unverified
Show 4 studies
- Displacement of Bilirubin from Albumin by Berberine
- Evaluation of raw and processed Phellodendri Chinensis Cortex using the quality marker analysis strategy by UHPLC-Q-Orbitrap MS and multivariate statistical analysis
- The Effects of Salt-Water Processing of Phellodendri Chinensis Cortex on the Enhancement of Kidney Absorption of the Main Alkaloids
- A strategy for evaluating the impact of processing of Chinese meteria medica on meridian tropism: the influence of salt-water processing of phellodendri chinensis cortex on renal transport proteins
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
Effects of berberine on the blood concentration of cyclosporin A in renal transplanted recipients: clinical and pharmacokinetic study
A randomised controlled trial in renal transplant recipients taking ciclosporin, with berberine 0.2 g three times daily for three months, plus a pharmacokinetic substudy in six patients. Ciclosporin trough concentrations rose 88.9 percent and the concentration/dose ratio 98.4 percent versus baseline; twelve days of berberine raised ciclosporin AUC by 34.5 percent and reduced apparent oral clearance by 40.4 percent. The authors attributed the effect to CYP3A4 inhibition in liver and gut.
Repeated administration of berberine inhibits cytochromes P450 in humans
Healthy volunteers took berberine 300 mg three times daily for two weeks and were phenotyped with probe substrates before and after. Berberine inhibited CYP2D6, CYP2C9 and CYP3A4 activity. This is the main human evidence that the interaction risk from berberine-bearing herbs is not confined to ciclosporin.
Berberine‐induced Haemolysis Revisited: Safety of Rhizoma coptidis and Cortex phellodendri in Chronic Haematological Diseases
A clinical and literature re-examination of the haemolysis allegation that led Singapore to ban Coptis and Phellodendron in 1978. The authors found the evidence for berberine-induced haemolysis conflicting rather than conclusive, and concluded that the two herbs can be used in patients with chronic haematological disease provided haemoglobin and bilirubin are monitored. It does not overturn the separate neonatal bilirubin-displacement concern.
Displacement of Bilirubin from Albumin by Berberine
Berberine was about tenfold more potent than phenylbutazone and about a hundredfold more potent than papaverine at displacing bilirubin from albumin in vitro. Chronic berberine administration in rats significantly lowered mean bilirubin serum protein binding and produced a persistent rise in steady-state unbound and total bilirubin. This is the mechanistic basis for the kernicterus contraindication in neonates.
Evaluation of raw and processed Phellodendri Chinensis Cortex using the quality marker analysis strategy by UHPLC-Q-Orbitrap MS and multivariate statistical analysis
Raw, salt-processed and charred Phellodendri Chinensis Cortex, the three forms the Chinese Pharmacopoeia recognises, were profiled by UHPLC-Q-Orbitrap MS and separated by multivariate analysis. The three processed forms are chemically distinguishable, which is the analytical justification for dispensing them separately: raw and salt-processed material is used for damp-heat diarrhoea and jaundice, and the charred form for bleeding.
The Effects of Salt-Water Processing of Phellodendri Chinensis Cortex on the Enhancement of Kidney Absorption of the Main Alkaloids
Salt-water processing, the preparation traditionally said to direct the herb to the Kidney, increased renal uptake of the main alkaloids relative to the raw bark. It gives a pharmacokinetic reading of the classical claim that salt-processed Huang Bai is the form for draining Kidney fire.
A strategy for evaluating the impact of processing of Chinese meteria medica on meridian tropism: the influence of salt-water processing of phellodendri chinensis cortex on renal transport proteins
Compared with the raw bark, salt-processed Phellodendri Chinensis Cortex increased the uptake capacity and expression of the renal organic cation transporter OCT2 and decreased the efflux capacity and expression of P-glycoprotein and MRP2. The authors read this as a transporter-level mechanism for the increased renal targeting of the salt-processed drug.
Historical Texts
Shen Nong Ben Cao Jing
Han dynastyGe Zhi Yu Lun (Zhu Zhen-heng / Zhu Dan-xi)
Yuan dynastyBen Cao Gang Mu
Ming dynastyReferences
- Sun, Yue; Lenon, George Binh; Yang, Angela Wei Hong. Phellodendri Cortex: A Phytochemical, Pharmacological, and Pharmacokinetic Review . Evidence-Based Complementary and Alternative Medicine (2019) [DOI]
- Qiu, W.; Jiang, X. H.; Liu, C. X.; Ju, Y.; Jin, J. X.. Effect of berberine on the pharmacokinetics of substrates of CYP3A and P‐gp . Phytotherapy Research (2009) [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 Huang Bai.
No notes yet.