Shi Yan
StarFossilia Spiriferis (fossilized shells of Cyrtospirifer sinensis (Grabau) and allied spiriferid brachiopods)
Synonyms: Cyrtospirifer sinensis (Grabau), Spirifer fossil shell, Shi Yan Zi, 石燕
☯ TCM Properties
Clears Damp-Heat, promotes diuresis and removes nebulae
Traditional Chinese Uses
Salty and cool, entering the Kidney and Bladder channels, Shi Yan is classed among the substances that clear Damp-Heat and promote urination. It is used for painful, difficult or turbid urination and stony/heat-type stranguria (lin syndrome), for chronic leucorrhoea, and for Damp-Heat lodged in the lower burner. Because it is salty and "removes nebulae," powdered Shi Yan (often levigated with water) was applied to the eyes for corneal opacities and superficial films, and taken internally for intestinal wind bleeding, haematochezia and anal fistula discharge. It is typically decocted 9–15 g, crushed and cooked first (or calcined and ground for topical/eye use). As a hard mineral fossil it is decocted long; use cautiously in the absence of genuine Damp-Heat.
Botanical Description
Shi Yan (石燕, "stone swallow") is a fossil, not a plant. The medicinal material is the petrified shell of extinct spiriferid brachiopods, chiefly Cyrtospirifer sinensis (Grabau) and related Devonian species, embedded in limestone or shale. The winged, ridged valves superficially resemble a swallow in flight, giving the drug its name. Specimens are grey, brownish-grey or yellowish, hard, heavy and stony, with a fan-shaped body bearing radiating plications and a hinge line drawn out into two lateral "wings." For use, the fossil shells are dug out, washed free of matrix, dried, and either ground to powder or, more often, calcined and quenched (cu zhi) to make them friable before decoction.
Occurs as fossilized brachiopod shells preserved in Devonian marine limestone and calcareous shale strata; collected from rock outcrops and quarries.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction | 9-15g | Daily | — | — | — |
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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