Pi Shi砒石
Arsenicum · Arsenolite · Crude Arsenic Trioxide · Xin Shi
Overview
- ·.*
The mineral arsenic of the classical materia medica, also called: the reddish, coloured by realgar impurity, and the purer white. Chemically it is arsenic trioxide. Acrid, sour, extremely hot and marked, it was applied to a haemorrhoid, a stubborn ringworm patch, a gangrenous gum or an ulcer with dead tissue that had to be eaten away, and — in doses of two to four thousandths of a gram — swallowed for cold-phlegm wheezing and for the malarial fever cycle. Those internal uses have been abandoned. Arsenic is a cumulative poison and a recognised human carcinogen, and the crude mineral is prohibited in most Western jurisdictions. This entry is a record of the classical drug, not a treatment recommendation.
Nature & Flavor
Acrid · Very hot · Very toxicChannels
Lung · LiverTypical Dosage
0.002–0.004 gActions
4 core actions
- Eats away dead tissueHaemorrhoids, stubborn ringworm, gangrenous gum disease, scrofulous nodes and ulcers whose dead tissue will not separate — the classical external use, always heavily diluted in a compounded powder or paste.
- Attacks toxinChronic toxic sores that resist everything else, in the classical external record.
- Cuts through cold phlegm wheezingThe classical internal use for entrenched cold-phlegm asthma — the pattern behind Zi Jin Dan 紫金丹, where a few milligrams were combined with fermented soybean. Obsolete: there is no circumstance in which this should be attempted now.
- Interrupts the malarial cycleRecorded classically for intermittent fever. Malaria is diagnosed and treated with artemisinin-based therapy; this is history, not an option.
In Formulas
Formulas containing Pi Shi
No published formula lists this herb yet — the library is growing.
Indications & Clinical Uses
- Haemorrhoids, stubborn ringworm, gangrenous gums, sloughy ulcers (classical external use, heavily diluted)
- Scrofulous nodes and chronic toxic sores (classical external use)
- Cold-phlegm wheezing and intermittent fever (classical internal use, obsolete)
- No part of this entry describes current practice
Western Medical Keywords
Searchable condition terms
Contraindications
Cautions
Pi Shi is arsenic trioxide — strongly toxic, cumulative, and a recognised human carcinogen. Read this entry as a record of the classical materia medica, not as a treatment recommendation.
- Acute poisoning. Swallowed arsenic causes burning in the mouth and throat, violent vomiting, profuse watery diarrhoea, collapsing blood pressure, seizures, and death within hours to days from multi-organ failure. The lethal amount is small enough that the classical internal dose is written in thousandths of a gram.
- Chronic poisoning. Repeated small exposures produce thickening and dark spots on the palms and soles, patchy skin pigmentation, white transverse lines on the nails, numbness and burning in the hands and feet from nerve damage, anaemia, and liver and kidney injury.
- Cancer. Arsenic is classified as carcinogenic to humans, with established risks of skin, lung and bladder cancer after long exposure. This is not a theoretical concern about a large dose — it is a consequence of chronic low-level exposure.
- Absorbed through a wound. Applied to an ulcerated or eroded surface, arsenic enters the circulation; deaths have followed topical application of arsenical pastes over too large an area. Never treat more than a small lesion, never several at once, never for more than a very short course, and never on mucous membranes.
- Dose ceiling. The pharmacopoeia internal limit is 0.002–0.004 g a day. State it, do not use it. There is no acceptable self-directed use, internal or external.
- Never with alcohol, which increases absorption. Classical incompatibility: — mercury and arsenic preparations are not combined.
- Absolutely avoided in pregnancy, while breastfeeding, in children, in liver or kidney impairment, and in the weak or debilitated.
- Legal status. Arsenic-containing medicines are prohibited or tightly restricted in the EU, the UK, the US, Canada and Australia. Possession and supply of the crude mineral is generally unlawful for a practitioner outside China; confirm the position with your own regulator.
- The one legitimate modern use is a different thing entirely. Pharmaceutical-grade arsenic trioxide (ATO) is an approved hospital chemotherapy for acute promyelocytic leukaemia, given by intravenous infusion at a controlled dose with cardiac monitoring for QT prolongation and watch for differentiation syndrome. That is a purified, assayed, manufactured medicine used by an oncology team. It is not an argument for the crude mineral, and nothing in that indication transfers to herbal practice.
Contraindicated in pregnancy: Contraindicated in pregnancy and while breastfeeding — arsenic crosses the placenta and is passed in breast milk, and it is toxic to the developing fetus. There is no safe amount in either setting.
For licensed practitioners’ reference only
References
- Pi Shi enters the Chinese materia medica through the Five Dynasties–Song 本草 literature; accounts differ on the first source text and it is not asserted here.
2. Bensky, Clavey & Stöger. Chinese Herbal Medicine: Materia Medica, 3rd ed.
3. 《中华人民共和国药典》(the 0.002–0.004 g internal limit).
4. The International Agency for Research on Cancer classifies arsenic and inorganic arsenic compounds as carcinogenic to humans (Group 1).
5. Arsenic trioxide injection is an approved treatment for acute promyelocytic leukaemia; see the product's approved prescribing information, which describes a hospital-administered pharmaceutical, not the crude mineral.
6. Arsenic in medicinal products is prohibited or restricted in most Western jurisdictions — confirm the current position with your own regulator.
Professional reference notice. Entries are scholarly references for licensed TCM practitioners and students — not medical advice, and not a recommendation to self-prescribe. Chinese herbal formulas should be used under the guidance of a qualified practitioner. Content is an original editorial compilation by Cura x Cura, cross-checked against the cited references.