The Herbs Most Often Faked, and How the Classics Tell Them Apart

The Herbs Most Often Faked, and How the Classics Tell Them Apart

The fakes are old, and so are the tells

Any herb worth money has been counterfeited, and for a long time. What is striking is that the classical materia medica did not merely list the valuable herbs and move on — it recorded, in concrete detail, how to tell the genuine root from the ones sold in its place. Centuries before any laboratory assay, the texts were already doing authentication: by provenance, by shape, by the cut, by whether a thing sinks in water. For some herbs the Bencao Gangmu goes further and names the substitute outright.

This article transcribes those identifying lines for five commonly faked herbs, each traced to its source. It is a record of how the classics described telling real from false — a demonstration of source-traceability pointed at the problem of authentication. It is not a buying guide, it makes no claim about what any herb does, and it carries no dosage. The question is narrower: what did the texts say to look at, and can you check the quote? (For the classic case — ginseng, whose substitutes the texts name one by one — we gave it its own article; here are five more.)

1. Huang qi (astragalus) — the classics name the fake: alfalfa root

Huang qi is one of the herbs where the Bencao Gangmu does not leave the substitute unnamed. Su Song, quoted in the collected explanations, says plainly what was being passed off as it:

今人多以苜蓿根假作黃耆，折皮亦似綿，頗能亂真。但苜蓿根堅而脆，黃耆至柔韌，皮微黃褐色，肉中白色，此為異耳。

That is: people commonly fake huang qi with alfalfa root (mu xu); when you snap the bark it, too, looks cottony, and it can quite pass for the real thing. But — and here is the tell — alfalfa root is hard and brittle, while huang qi is very soft and tough, its bark faintly yellow-brown and its flesh white inside. Wang Haogu adds that the counterfeit even had a market nickname, 土黃耆 ("earth huang qi"), and that it is bitter where true huang qi is sweet.

Notice the name itself is a tell. True huang qi is called 綿黃耆 ("cotton huang qi") because 其皮折之如綿 — its bark, when broken, pulls apart like cotton wool. The identification is written into the very word: snap it, and a real root frays like fibre; a fake snaps clean.

2. Xi xin (asarum) — the classics name the fake: du heng

Xi xin is the second herb the texts name a substitute for. Su Song again:

今人多以杜衡為之。杜衡根似飯帚密鬧，細長四五寸，微黃白色，江淮呼為馬蹄香，不可誤用。

"People commonly use du heng in its place." Du heng's root is like a bundled broom, slender, four or five inches, faintly yellow-white — not to be mistaken for xi xin. And the Mengxi Bitan (Shen Kuo), quoted in the entry, describes the genuine article precisely and then catches the trick:

細辛出華山，極細而直，柔韌，深紫色，味極辛……細辛水漬令直，是以杜衡偽為之也。

Real xi xin from Mount Hua is very fine and straight, tough, deep purple, intensely acrid. The forgers, it says, wet du heng to straighten it and pass it off — so much so that the xi xin used in the southeast "is all du heng." Li Shizhen then reduces the difference to a two-line key: xi xin has a soft stem and fine root, straight and purple, intensely acrid; du heng has a root that bends, yellow-white in colour. Straight-and-purple versus bent-and-pale — that is the whole test.

3. Dang gui (angelica) — read the head and the tail

For dang gui the texts do not name a single rival plant so much as grade the root by its own shape and origin. Su Gong distinguishes two forms — the 马尾当归 ("horsetail dang gui"), long favoured, and a 蚕头当归 ("silkworm-head dang gui") that he calls unfit — and Li Shizhen sharpens it into a description you can hold a root against:

以秦歸頭圓尾多色紫氣香肥潤者，名馬尾歸，最勝他處；頭大尾粗色白堅枯者，為鑱頭歸。

The prized horsetail dang gui has a round head and many tails, purple in colour, fragrant, plump and moist; the lesser spade-head dang gui has a big head, coarse tail, white colour, hard and dry. Round-plump-purple-moist against big-coarse-white-dry: the tell is entirely in the head, the tail, and the colour of the root in your hand.

4. Da huang (rhubarb) — look for the brocade, beware "earth rhubarb"

Da huang is authenticated by a mark in its cross-section and by where it comes from. Su Song ranks the sources and flags the impostor by name:

以蜀川錦文者佳……江淮出者曰土大黃。

The best is the Sichuan "brocade-pattern" (錦文) da huang — cut it across and the genuine root shows a marbled, brocade-like figure — while what comes out of Jianghuai is called 土大黃 ("earth rhubarb"). And in his 正誤 (corrections) section Li Shizhen is blunt that the earth rhubarb is a different plant wearing the name:

蘇說即老羊蹄根也。因其似大黃，故謂之羊蹄大黃，實非一類。

The so-called earth rhubarb, he says, is really aged yang-ti (dock) root; it is called "dock rhubarb" only because it resembles da huang — it is not the same class at all. The brocade cross-section is the tell; the name "earth rhubarb" is the warning.

5. Chen xiang (agarwood) — the test is water

Chen xiang is the herb whose entire identity is a physical test. Li Shizhen gives the etymology and the grade in one breath:

木之心節置水則沉，故名沉水……半沉者為棧香，不沉者為黃熟香。

The resinous heart-node placed in water sinks — hence the name chen shui ("sink-water"). What *half-*sinks is zhan xiang; what does not sink is huang shu xiang. Chen Cheng draws the practical line for authentication:

要之入藥惟取中實沉水者。

"In essence, for medicine take only the solid kind that sinks in water." Where the other four herbs are told apart by shape or cross-section, chen xiang is told apart by density: drop it in water and the genuine, resin-laden heartwood goes to the bottom. The float-or-sink is the whole grade.

How MateriaTrace handles it: every identifying line traced

So "which herbs get faked" turns, in the classics, into a stack of specific, checkable records:

1. huang qi — the fake named (alfalfa root), told apart by soft-and-tough versus hard-and-brittle, and by the "cotton" fray;
2. xi xin — the fake named (du heng), told apart by straight-and-purple versus bent-and-pale;
3. dang gui — graded by head, tail, and colour (horsetail versus spade-head);
4. da huang — the brocade cross-section against the "earth rhubarb" impostor;
5. chen xiang — graded by whether it sinks in water.

Here is how we hold that: each line is kept verbatim, attributed to the authority who said it (蘇頌, 弘景, 沈括, 陳承, 時珍), placed in its section of the Bencao Gangmu, and traced to the source. Where the text names a substitute that is itself a catalogued herb — alfalfa root, du heng — we link both ends, so the record of the fake sits next to the record of the real thing. We add no modern verdict on what any herb is or does; we record how the classics described recognizing it.

Worth stating plainly: this is a record of how classical texts described distinguishing genuine herbs from substitutes, kept for study and traceability. It is not advice on buying, identifying for purchase, using, or dosing any herb, and it makes no claim about any herb's effects. MateriaTrace records what sources say and makes no treatment recommendation; any question about a herb belongs with a qualified professional.

Why this is what source-traceability is for

It would be easy to write one line per herb — "real huang qi is soft; fakes are brittle" — and be done. But that line would throw away what the classics actually built: a named substitute, a snap test, a brocade cross-section, a sink-or-float grade, each attached to the authority who recorded it. Those survive only if the exact lines survive, each traceable — so that a later reader can do what Li Shizhen did to the fakers, and check.

See the roots themselves: huang qi and the alfalfa (mu xu) named as its fake; xi xin and the du heng sold in its place; dang gui, da huang, and chen xiang. For the herb whose substitutes the classics name one by one, read how the texts verify real ginseng; for a record where the sources themselves disagree, read about cinnabar and mercury.

If this "every line clicks back to its own source" approach is useful to you, see what else is in MateriaTrace on the homepage.

MateriaTrace is a source-traceable, bilingual knowledge graph of Chinese medicine. It records how classical and modern sources describe each entry — each field traceable to its primary source, contradictions kept side by side — and makes no treatment or usage recommendations. Every line quoted in this article can be traced to its classical source.