Ban Mao斑蝥
Mylabris · Blister Beetle · Mylabris · Chinese Cantharides
Overview
- ·. Editions differ on where this beetle belongs — some file it here among the surface remedies that attack toxin, others with the blood-breaking herbs. The reviewer may wish to move it.*
The dried body of the blister beetle, acrid, hot and among the small number of items the materia medica marks — strongly toxic. Its single active compound, cantharidin, raises a blister on any skin it stays in contact with, and that blistering is the whole of its classical external use: it was painted on a wart, a ringworm patch or a stubborn node to lift and destroy the tissue. Tiny processed internal doses appear in the record for scrofula, hard abdominal masses and rabies prophylaxis. Cantharidin is also a kidney poison with a very short distance between a blister and a death, so nothing here is a self-directed procedure.
Nature & Flavor
Acrid · Hot · Very toxicChannels
Liver · Kidney · StomachTypical Dosage
0.03–0.06 gActions
4 core actions
- Attacks toxin, erodes the lesionWarts, corns, stubborn ringworm patches, scrofulous nodes and unhealing sores — applied to the lesion itself, classically after steeping the powder in wine or vinegar.
- Raises a blister, draws rednessThe point of the external application: cantharidin separates the upper layer of skin from the layer beneath, and the blister that forms carries the treated tissue away with it. Classically it was also applied over an acupoint to raise a deliberate blister.
- Breaks blood stasis, disperses massesAmenorrhea from congealed blood and hard abdominal masses in the classical record — internal use at a fraction of a gram, and rarely undertaken.
- Processed, never raw, for internal useInternal preparations are stir-fried with rice to reduce, though not remove, the cantharidin. Raw Ban Mao is never swallowed. The head, wings and legs are removed first.
In Formulas
Formulas containing Ban Mao
No published formula lists this herb yet — the library is growing.
Indications & Clinical Uses
- Warts, corns and stubborn ringworm patches — topical, on the lesion only
- Scrofulous nodes and unhealing chronic sores (classical external use)
- Amenorrhea from blood stasis and hard abdominal masses (classical internal use, rarely undertaken)
- Modern practice relies on the purified derivative rather than the crude beetle
Western Medical Keywords
Searchable condition terms
Contraindications
Cautions
Ban Mao is strongly toxic. Cantharidin blisters skin on contact and poisons the kidney when absorbed; fatal ingestions are on record.
- Blistering is not a side effect, it is the drug. Contact with healthy skin raises painful blisters and can leave scarring or pigment change. Apply only to the lesion, for a short time, on a small area, and cover the surrounding skin. Never use it on the face, the genitals, mucous membranes or near the eyes, never on broken or weeping skin, and never on infants or small children.
- Absorption through blistered skin is real. Large or repeated topical applications have produced systemic poisoning, not merely a local reaction.
- The kidney is the target organ. Swallowed cantharidin corrodes the mouth, throat and gut — burning pain, vomiting, bloody diarrhoea — and then damages the renal tubules, producing blood in the urine, painful or absent urination and acute kidney failure. Painful priapism and cardiovascular collapse are also recorded. Human lethal doses of cantharidin are reported in the range of a few tens of milligrams, which is why the internal ceiling is expressed in hundredths of a gram.
- Dose ceiling. 0.03–0.06 g a day, rice-processed, in pills or powder, on a practitioner's prescription and for the shortest possible course. There is no safe self-directed internal use.
- Absolutely avoided in pregnancy, while breastfeeding, in kidney or urinary tract disease, in heart disease, in the elderly or debilitated, and in children.
- The modern derivative is not the same thing. Norcantharidin and other purified cantharidin derivatives are manufactured drugs given under oncology supervision with monitoring. A hospital preparation of a purified compound is not an argument for handling the crude beetle.
- Handling. Wear gloves and avoid inhaling the powder; the dust irritates the airway and the eyes. Suspected ingestion is a medical emergency.
Contraindicated in pregnancy: Contraindicated in pregnancy and while breastfeeding, internally and externally — it is strongly toxic and classically listed as capable of causing miscarriage.
For licensed practitioners’ reference only
References
- Shen Nong Ben Cao Jing《神农本草经》(classical source, public domain).
2. Bensky, Clavey & Stöger. Chinese Herbal Medicine: Materia Medica, 3rd ed.
3. 《中华人民共和国药典》(the 0.03–0.06 g internal ceiling and the rice-processing requirement).
4. Editions of 《中药学》 differ on whether this entry sits with the external remedies or with the blood-breaking herbs — check your own edition.
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.