Chi Shi Zhi (Halloysite, Kaolin)

Chinese Herb Actions

Chinese Herb Dosage

• What is the typical dosage of Chi Shi Zhi?

  About 9–18 g in decoction, with some references giving 10–20 g and a ceiling near 30 g. Because it is a dense mineral rather than a plant part, it is conventionally crushed and decocted wrapped in cloth (bao jian) so the fine sediment does not end up as grit in the finished liquid, and in several classical uses part of the dose is given as a powder rather than decocted at all.

  • Powdered use — in Tao Hua Tang (Peach Blossom Decoction), which we hold, a portion of the Chi Shi Zhi is traditionally decocted with the other ingredients while a portion is stirred into the strained decoction as powder, on the reasoning that the undissolved clay is what actually coats and binds the intestines.
  • External use — applied topically as a fine powder to weeping sores and non-healing ulcers; no oral dose applies in that use.
  • Dose ceilings are reference data — mineral medicinals are dispensed by qualified practitioners; the figures above document what standard references record, not instructions for use.

  Source: our own herb record (dosage figures as held) and standard materia medica ranges (Bensky et al., 3rd ed.; Chen & Chen), cross-referenced against multiple online sources. Reference only — not a prescription.

Chinese Herb Contraindications & Cautions

• Are there cautions for Chi Shi Zhi?

  Chi Shi Zhi is a binding astringent, so the central caution is not to use it where something still needs to come out — it is traditionally contraindicated in excess damp-heat or stagnation, in hot-type diarrhea, and in the early stages of dysentery, where astringing too soon is held to trap the pathogenic factor inside. Our record also flags it for the utmost caution in pregnancy.

  • Classical incompatibility — not combined with Rou Gui, per the Nineteen Antagonisms and our own caution data (see notes above).
  • Mineral, so quality is a sourcing question — see the toxicity section for what is and is not documented about heavy metals in medicinal clays.
  • Adsorption is non-selective — a clay that binds material in the gut can in principle bind other things taken at the same time; see drug interactions.
  • Professional supervision — mineral medicinals should be prescribed and dispensed by a qualified practitioner. This page is reference information, not usage instructions.

  Source: our own herb record and recorded incompatibility data; category cautions per published materia medica consensus (Bensky et al., 3rd ed.), cross-referenced against multiple online sources. Reference note, not a safety guarantee.

Chinese Herb Toxicity & Overdose

• Does Chi Shi Zhi contain heavy metals? Is it safe?

  Chi Shi Zhi is a clay, and clays can carry lead, arsenic and other metals depending entirely on where they were mined — but we have found no published testing of this specific medicinal material, so the honest answer is that the question is real and the species-level evidence is thin. We report what is actually documented rather than importing generic claims about heavy metals in Chinese herbs.

  What is documented, and about what:

  • Clays sold for oral use, generally — a Dutch market survey analysed 63 clay products intended for eating or health use and found maximum levels of lead, arsenic, mercury and cadmium of 99.7, 45.1, 2.2 and 0.75 mg/kg respectively; for many samples, estimated intakes exceeded health-based guidance values for lead and inorganic arsenic, and the authors advised against use, particularly in pregnancy (PMID 23862762). These were traditional and “health” clays, not pharmacopoeial Chi Shi Zhi.
  • Release depends on gut conditions — a study of edible West African clays in simulated oral, gastric and intestinal media found that trace-element release is pH-dependent, with more copper, iron and zinc released at stomach pH, while lead, manganese and nickel stayed below quantification limits (PMID 18608568). Total content and absorbable content are not the same number.
  • Aluminium is intrinsic, not a contaminant — halloysite is an aluminium silicate, so aluminium is part of the mineral’s structure rather than an impurity. We have not located dosing studies measuring aluminium absorption from oral Chi Shi Zhi, and we make no claim in either direction.
  • Halloysite itself is generally described as biocompatible — the medical-mineralogy literature developing halloysite nanotubes for drug delivery and wound care characterizes the material as safe and biocompatible in that context (PMID 39016265), which is supportive background but is not a food-safety assessment of mined medicinal clay.

  Bottom line as a reference fact: the contamination question for mineral medicinals is legitimate and mine-dependent; tested, pharmacopoeial-grade material dispensed by a qualified practitioner is the relevant safeguard. We are not aware of published heavy-metal assays specific to commercial Chi Shi Zhi, and we do not assert either that it is contaminated or that it is clean.

  Sources: PMID 23862762 (DOI 10.1080/19440049.2013.811297); PMID 18608568 (DOI 10.1080/09637480701614956); PMID 39016265 (DOI 10.1021/acsnano.4c04372). Reference note, not a safety guarantee.

Herb-Drug Interactions

• Does Chi Shi Zhi interact with medications?

  No specific clinical interaction study has been published for Chi Shi Zhi. The reasonable precaution follows from what the material is rather than from data: adsorbent clays and mineral antacids are well recognized in pharmacy for binding co-administered drugs in the gut and reducing their absorption, and separating doses in time is the standard way that class of problem is handled. Applying that logic to Chi Shi Zhi is precautionary reasoning, not a demonstrated interaction.

  Practically, patients taking prescription medication — especially medicines with narrow dosing margins — should tell their prescriber and their practitioner about any clay-containing formula. (Flagged for practitioner confirmation; reference information only.)

Western / Biomedical Research

Chinese Herb Clinical Studies & Research

Provided as research context — a summary of published biomedical study, not a therapeutic or medical claim.

• Is there modern research on Chi Shi Zhi (halloysite)?

  Yes, but it splits into two literatures that rarely meet: materials science on halloysite as a nanomaterial, and Chinese-language pharmacology on the classical formulas that contain it. There is no clinical trial of Chi Shi Zhi as a single medicinal that we could verify.

  • What the mineral is, and how it behaves — a 2024 review in ACS Nano surveys halloysite clay (naming its Chinese medicine identity as Chishizhi) as one-dimensional aluminosilicate nanotubes, and reviews its use in hemostasis, wound repair, gastrointestinal applications and tissue engineering, attributing this to the hollow tubular structure, high surface area, surface charge and biocompatibility (PMID 39016265). The hemostatic and gut-coating properties described there map interestingly onto the herb’s two classical actions, though the review is about engineered material, not decocted clay.
  • Formula-level animal work — a metabolomics and proteomics study of Chishizhi Yuyuliang Decoction (the classical Chi Shi Zhi and Yu Yu Liang pairing) in a dextran-sulfate-sodium mouse model of ulcerative colitis reported reduced disease-activity scores and inflammatory cytokines, with effects linked to caveolin-1 and focal-adhesion signalling and to restored intestinal barrier function in cell models (PMID 42200545). Animal and cell work on a multi-ingredient formula, not evidence for the single mineral in people.
  • Contamination literature — the heavy-metal studies of oral clays summarized in the toxicity section (PMID 23862762, PMID 18608568) are the most decision-relevant research for anyone actually sourcing this material.

  Taken together: the physical chemistry gives a coherent account of how a clay could bind the intestines and staunch bleeding, and there is preclinical work on a formula containing it. Neither amounts to clinical evidence, and neither is a treatment claim.

  Sources: PMID 39016265 (DOI 10.1021/acsnano.4c04372); PMID 42200545 (DOI 10.1002/rcm.70106); PMID 23862762; PMID 18608568. Research context, not a therapeutic claim.

Chinese Herb Notes

• Is Chi Shi Zhi a plant? What actually is it?

  No — Chi Shi Zhi is a mineral, not a plant. It is a naturally occurring red clay: a hydrated aluminium silicate of the kaolin group, identified in the mineralogical literature as halloysite, which forms characteristic hollow one-dimensional nanotubes. Its red colour comes from iron oxide content, which is what the pharmaceutical name “Halloysitum Rubrum” and the Chinese name (literally “crimson stone resin”) both record. A 2024 review of medical mineralogy names halloysite’s Chinese medicine identity explicitly as Chishizhi.

  This matters for readers because clay behaves quite differently from a herb: it is not extracted so much as suspended, its action is substantially physical (adsorption and coating of the gut lining), and its quality question is geological — where the clay was mined — rather than botanical.

  Identity field flagged, not altered. Our record spells the Latin “Hallyositum Rubrum”; the mineral name is halloysite, so the standard pharmaceutical form is “Halloysitum Rubrum.” This looks like a dropped letter rather than a different material. Left unchanged for owner correction. Separately, the common name field pairs “Halloysite, Kaolin”: halloysite and kaolinite are closely related members of the same kaolin group and sources use the names loosely for this medicinal, but they are not strictly the same mineral species.

  Which herb must not be combined with Chi Shi Zhi?

  Rou Gui (cinnamon bark). This is the one antagonism our own recorded incompatibility data holds for Chi Shi Zhi, and it is a genuine classical entry: the pairing appears in the traditional list known as the Nineteen Antagonisms (shi jiu wei), a memorized set of substance pairs that classical pharmacy holds should not be prescribed together. In our records the relationship is stored on the Rou Gui side and reads “This herb antagonizes or is antagonized by: Chi Shi Zhi.”

  • What we hold — exactly one caution pair for this mineral: Chi Shi Zhi with Rou Gui. No other antagonism or incompatibility is recorded for it in our data.
  • Cross-check of our own formulas — the two do not co-occur in any formula we hold. Chi Shi Zhi appears in Tao Hua Tang and Zhen Ling Dan; Rou Gui appears elsewhere, including Yang He Tang. The classical rule and our formula data are consistent.
  • Status of the rule — the Nineteen Antagonisms are a classical prescribing convention, not a modern pharmacological finding; we have found no laboratory or clinical study testing this specific pair, and we do not claim one exists.

  What is Chi Shi Zhi combined with?

  In our own formula records it appears in Tao Hua Tang (Peach Blossom Decoction) with Gan Jiang and Geng Mi (rice) — the classic three-ingredient formula for chronic cold-deficiency dysentery with blood in the stool — and in Zhen Ling Dan (Rouse the Spirit Special Pill) alongside Yu Liang Shi (limonite), Zi Shi Ying, Dai Zhe Shi, Ru Xiang and Mo Yao, a heavily mineral formula for uterine bleeding. The Chi Shi Zhi and Yu Yu Liang pairing seen there is the standard mineral astringent duo, and it also gives its name to a classical decoction of the same two substances. (Traditional formula context, not treatment advice.)

  Two further points from our record worth keeping: Chi Shi Zhi has a traditional reputation as an antidote for ingested poisons, on the reasoning that the clay binds the substance and carries it out through the bowel — a plausible-sounding classical rationale, recorded here as tradition rather than as a claim about poisoning management. And because it treats the branch rather than the root, the tradition is explicit that tonifying substances should be added to address the underlying deficiency.

  Source: our own herb, incompatibility and formula records; mineral identification per PMID 39016265; classical incompatibility per published materia medica consensus (Bensky et al., 3rd ed.), cross-referenced against multiple online sources.

This herb antagonizes or is antagonized by:

• Rou Gui (Cortex Cinnamomi Cassiae)