Traditionally used for
- Bowel health
- Menstrual & women's health
☯ TCM Properties
Astringes the Intestines and Stops Diarrhea; Astringes and Stops Bleeding; Astringes to Stop Vaginal Discharge
Traditional Chinese Uses
Yu Yu Liang (limonite) is a warm, astringent iron-oxide mineral substance used to stop chronic diarrhea and control abnormal bleeding. It is indicated for persistent loose stools resistant to other treatments, as well as prolonged uterine bleeding and excessive vaginal discharge. Its mechanism is primarily astringent and binding, so it addresses the symptom rather than the underlying root cause and is typically combined with herbs that tonify the deficiency driving the leakage.
Relationships
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Botanical Description
Yu Yu Liang is the medicinal form of limonite, a naturally occurring amorphous hydrated iron oxide-hydroxide of variable composition usually approximated as FeO(OH)·nH2O, with goethite and lepidocrocite as the principal crystalline phases. The material is a common secondary iron ore formed by the weathering of iron-bearing rocks, gossans over sulfide deposits, and bog-iron environments; the medicinal grade comprises rounded brown to yellow-brown concretions or nodules with a smooth waxy or earthy surface, often hollow and rattling with loose powder inside (the “tai-yi yu liang” concretion form). The nodules are crushed and calcined, then ground to a fine powder for use. In traditional Chinese medicine the prepared mineral is sweet, astringent, and slightly cold, securing the lower jiao to stop chronic diarrhea and uterine bleeding, and astringing leukorrhea, with classical use in formulas such as Yu Yu Liang Wan for prolonged dysenteric disorders.
Active Constituents
Goethite, alpha-FeO(OH)
Iron oxyhydroxide mineralConcentration: The dominant crystalline phase. Limonite is not a mineral species at all but a field term for a fine-grained mixture of hydrous iron oxides; the crystallographic work that settled the question concluded that what had been called limonite is goethite (Holser, Acta Crystallographica 1953). The Chinese Pharmacopoeia definition, basic ferric oxide FeO(OH), is therefore a nominal formula for a mixture, not the composition of a single phase.
Ferric oxyhydroxide is poorly soluble at intestinal pH, so most of an oral dose passes through unabsorbed and acts as a bulk adsorbent and mild astringent rather than as a source of systemic iron. The fraction that dissolves in gastric acid is the part that can chelate co-administered drugs and contribute to iron load, and no study has measured that fraction for the medicinal drug.
Lepidocrocite, hematite and amorphous ferrihydrite
Accessory iron oxide and oxyhydroxide phasesConcentration: Variable minor phases in natural limonite. The relative proportions differ between deposits and are not controlled by any monograph.
These phases differ from goethite in surface area and acid solubility, so batch-to-batch variation in the mix is one reason the dissolved-iron dose from the drug is not predictable.
Clay, silica and alumina gangue
Non-iron mineral matterConcentration: Limonite nodules typically enclose clay and silica; the Chinese analytical literature on the drug has used Fe2O3 and Al2O3 together to characterise the ore. No pharmacopoeial content limit for iron, silica or alumina is set for this drug.
The aluminosilicate fraction contributes adsorptive surface of its own, so the drug is not a pure iron preparation even in a clean batch.
Arsenic
Metalloid contaminant (geochemically enriched)Concentration: No published assay of medicinal Limonitum was located, so no figure can be quoted for this drug. What can be stated is the geochemical reason for concern: goethite and amorphous ferric oxyhydroxide are among the strongest natural scavengers of arsenate from groundwater, and arsenic sorbed to goethite is only partly reversible (Zhang et al. 2017; Mamindy-Pajany et al. 2011). Natural iron oxyhydroxide ores are therefore expected to carry arsenic, and Chinese analytical work on this drug has specifically used lead and arsenic as its marker harmful elements.
This is the safety-critical gap in the record. The Chinese Pharmacopoeia sets no arsenic limit for this monograph, and its general ceilings for lead, cadmium, arsenic, mercury and copper apply to plant-derived materials and decoction pieces rather than to mineral drugs, so nothing in routine quality control would catch an arsenic-rich batch.
Lead, cadmium and mercury
Heavy metal contaminants (not assayed in this drug)Concentration: Not measured in any accessible published survey of medicinal Limonitum. No pharmacopoeial limit test for these elements applies to the monograph.
Recorded as an explicit gap rather than as a reassurance. Absence of an assay is not evidence of absence for a dug ore.
Ferrous iron generated by calcination and vinegar quenching
Processing-derived soluble iron speciesConcentration: Not quantified for this drug in any source located. The Chinese Pharmacopoeia processing method is to break the cleaned mineral into fragments, calcine until red throughout and quench, using 30 kg of vinegar per 100 kg of drug. The same 30 kg per 100 kg vinegar ratio is specified for calcined Magnetitum, where ferrous iron dissolution has been formally adopted as a critical quality attribute of the process.
Calcining and quenching in acetic acid cracks the ore and converts part of the surface to acetate-soluble iron, which is why the processed drug and the raw drug are not pharmacologically interchangeable. It also means that processing raises rather than lowers the potential for the iron chelation interactions listed below, while the parallel work on Magnetitum shows calcination can simultaneously lower the lead and cadmium burden.
⚠ Drug Interactions
Levothyroxine
Iron binds thyroxine directly. In 14 patients with primary hypothyroidism on stable replacement who took 300 mg ferrous sulfate with their thyroxine daily for 12 weeks, mean serum TSH rose from 1.6 to 5.4 mU/L and nine of the 14 became more symptomatic; mixing iron and thyroxine in vitro produced a poorly soluble purple complex (Campbell et al., Annals of Internal Medicine 1992). That trial used soluble ferrous sulfate. Limonite is ferric oxyhydroxide and is far less soluble than ferrous sulfate, so the dissolved iron dose from an ordinary decoction is smaller and has never been measured; calcination and vinegar quenching raise the soluble fraction, which moves the processed drug closer to the studied condition, but no figure exists for either form.
Clinical note: Separate the mineral from levothyroxine by at least four hours. If a euthyroid patient is started on the mineral for more than a few weeks, recheck TSH.
Fluoroquinolone antibiotics
Fluoroquinolones chelate divalent and trivalent metal cations at the 3-carboxyl and 4-oxo positions, forming poorly absorbed complexes. In three two-period crossover trials of eight healthy volunteers each, ferrous sulfate equivalent to 100 mg elemental iron reduced the AUC of norfloxacin by 73 percent, ciprofloxacin by 57 percent and ofloxacin by 25 percent (Lehto, Kivisto and Neuvonen, British Journal of Clinical Pharmacology 1994); an earlier study found the same for ciprofloxacin (Polk et al. 1989). Limonite is ferric oxyhydroxide and is far less soluble than ferrous sulfate, so the dissolved iron dose from an ordinary decoction is smaller and has never been measured; calcination and vinegar quenching raise the soluble fraction, which moves the processed drug closer to the studied condition, but no figure exists for either form.
Clinical note: Do not co-administer. Separate by at least two hours before or six hours after the quinolone, and preferably suspend the mineral for the duration of the antibiotic course.
Tetracycline antibiotics
Tetracyclines form stable chelates with iron. Neuvonen and Turakka showed in man that a range of iron salts inhibits tetracycline absorption (European Journal of Clinical Pharmacology 1974), and the affinity of tetracycline for aluminium and iron hydrous oxide surfaces is well characterised. Limonite is ferric oxyhydroxide and is far less soluble than ferrous sulfate, so the dissolved iron dose from an ordinary decoction is smaller and has never been measured; calcination and vinegar quenching raise the soluble fraction, which moves the processed drug closer to the studied condition, but no figure exists for either form.
Clinical note: Separate by at least two hours, or suspend the mineral while the tetracycline course runs.
Levodopa
Levodopa is a catechol and chelates ferric iron strongly. In a randomised crossover trial in eight normal subjects, 325 mg ferrous sulfate taken with 250 mg levodopa reduced peak levodopa concentration by 55 percent and AUC by 51 percent; ferrous iron is oxidised rapidly to the ferric state in the presence of levodopa at small-intestinal pH, and it is the ferric complex that binds (Campbell and Hasinoff, Clinical Pharmacology and Therapeutics 1989). Limonite is ferric oxyhydroxide and is far less soluble than ferrous sulfate, so the dissolved iron dose from an ordinary decoction is smaller and has never been measured; calcination and vinegar quenching raise the soluble fraction, which moves the processed drug closer to the studied condition, but no figure exists for either form.
Clinical note: Separate by at least two hours in any patient on levodopa, and ask about new off-periods if the mineral has recently been added.
Oral iron supplements and iron-overload states
Yu Yu Liang is an iron ore, and the traditional processing of these drugs by calcination and vinegar quenching is aimed precisely at raising the dissolved ferrous fraction. No study has measured how much iron a patient actually absorbs from a decoction of the drug, so the added load cannot be quantified, but it is not zero and it is additive to any prescribed iron.
Clinical note: Avoid in haemochromatosis, transfusion-dependent anaemia and other iron-overload states. Count the mineral as an unquantified iron source when reviewing a patient already on iron replacement.
Yu Liang Shi (Limonitum) supplied under either name
Yu liang shi, yu liang tu, bai yu liang and yu liang shi are all recorded aliases of yu yu liang, and all denote Limonitum. A formula or database that carries both names carries one drug twice.
Clinical note: Treat the two entries as one drug when totalling a prescription, and confirm intent with the prescriber if both appear.
Shi Zhong Huang and Tai Yi Yu Liang
A Yu Yu Liang nodule has a hard limonite shell and a soft ochreous filling, and the classical literature gives those parts separate names, with Lei Gong Pao Zhi Lun explicitly warning against confusing them. The shell and the filling differ in iron content, particle size and adsorptive surface, so material sold under one name may not behave like material sold under another.
Clinical note: Specify which material is wanted when ordering, and do not assume that two suppliers of Yu Yu Liang are shipping the same part of the same ore body.
Chelation therapy and heavy-metal exposure workup
Mineral drugs are dug ores, and the Chinese Pharmacopoeia limits for lead, cadmium, arsenic, mercury and copper are written for plant-derived materials and decoction pieces, not for the mineral monographs. A patient taking one of these minerals long term is therefore on an uncharacterised source of arsenic and lead, which will confuse the interpretation of a blood lead, a urine arsenic or a response to chelation.
Clinical note: If a patient on a mineral drug has an unexplained raised blood lead or urinary arsenic, treat the herb itself as a candidate source and have the actual batch assayed rather than assuming an occupational or dietary cause.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction (pre-decocted) | 9–15 g | Daily | — | — | 中国药典 2020 【用法与用量】9～15g，先煎；或入丸散。 【注意】孕妇慎用。 【性味与归经】甘、涩，微寒。归胃、大肠经。 — 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.
Two heavy, astringent minerals bind the lower burner together, stopping chronic, incontinent diarrhea that has not responded to regulating the middle.
Not for diarrhea with an unresolved pathogen or accumulation.
Core pair of a classical formula — Chi Shi Zhi Yu Yu Liang Tang, Shang Han Lun (Zhang Zhongjing)
Evidence Tier
Strong 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
3
2 verified · 1 unverified
Other clinical trial
2
2 verified · 0 unverified
Observational / case report
0
In vitro / animal
0
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
The effect of ferrous sulphate on the absorption of norfloxacin, ciprofloxacin and ofloxacin.
Three separate two-period crossover trials, eight healthy volunteers each, single doses after an overnight fast. Ferrous sulfate corresponding to 100 mg elemental iron reduced the 0 to 24 hour AUC of norfloxacin by 73 percent, ciprofloxacin by 57 percent and ofloxacin by 25 percent, with matching falls in peak concentration and urinary recovery. The iron source was soluble ferrous sulfate, not a mineral iron oxide.
Effect of ferrous sulfate and multivitamins with zinc on absorption of ciprofloxacin in normal volunteers
Volunteer crossover study confirming that ferrous sulfate, and multivitamin preparations containing zinc, substantially reduce ciprofloxacin absorption. Establishes the interaction as a metal-cation chelation effect rather than something specific to one iron salt.
Inhibitory effect of various iron salts on the absorption of tetracycline in man
Human study comparing several iron salts for their effect on tetracycline absorption, finding inhibition across the range tested. It is the primary human evidence that the tetracycline-iron interaction is a property of iron rather than of one particular salt, which is what makes extrapolation to a mineral iron drug reasonable in direction if not in magnitude.
Ferrous Sulfate Reduces Thyroxine Efficacy in Patients with Hypothyroidism
Uncontrolled clinical trial in 14 patients with primary hypothyroidism on stable thyroxine, who took 300 mg ferrous sulfate with their thyroxine daily for 12 weeks. Mean TSH rose from 1.6 to 5.4 mU/L and nine of 14 developed more hypothyroid symptoms and signs, while the free thyroxine index did not change significantly. Mixing the two in vitro produced a poorly soluble purple iron-thyroxine complex.
Ferrous sulfate reduces levodopa bioavailability: Chelation as a possible mechanism
Randomised crossover trial in eight normal subjects. A 325 mg ferrous sulfate tablet taken with 250 mg levodopa reduced peak levodopa concentration by 55 percent and AUC by 51 percent. Ferrous iron oxidises rapidly to ferric in the presence of levodopa at small-intestinal pH, and the ferric complex binds strongly; the authors noted the clinical significance remained to be established.
Historical Texts
Shen Nong Ben Cao Jing
Eastern Han, c. 200 CEShang Han Lun (Zhang Zhongjing)
Eastern Han, c. 200 CELei Gong Pao Zhi Lun
Southern and Northern Dynasties, attributed to Lei Xiao, c. 5th centuryBen Cao Gang Mu (Li Shizhen)
Ming, 1596References
- Holser WT. Limonite is goethite . Acta Crystallographica (1953) [DOI]
- Zhang M; Dai M; Xia L; Song S. Comparison of Arsenic Adsorption on Goethite and Amorphous Ferric Oxyhydroxide in Water . Water, Air, and Soil Pollution (2017) [DOI]
- Mamindy-Pajany Y; Hurel C; Marmier N; Romeo M. Arsenic (V) adsorption from aqueous solution onto goethite, hematite, magnetite and zero-valent iron: Effects of pH, concentration and reversibility . Desalination (2011) [DOI]
- Han X; Luo JY; Liu QT; Li YJ; Xie YJ; Yang SH; Yang MH. Study on species and valence state of heavy metals and deleterious elements of mineral medicine . China Journal of Chinese Materia Medica (2015) [DOI]
- Xu Shan; Xu Liu; Xiang Tangyong; Zhu Ling; Gu Yi; Cai Baochang; Chen Zhipeng. Research Progress on Metallic Mineral Chinese Medicines . Journal of Nanjing University of Traditional Chinese Medicine (2021)
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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