Polygonum multiflorum Seeds | Polygoni Multiflori Slices He Shou Wu
LATIN NAME: Polygonum multiflorum
COMMON NAME: He Shou Wu Slices, Fo-ti, Chinese Knotweed Root
Plant Profile
He shou wu is a twining vine of the knotweed family, growing five metres or more each season from a tuberous root that can weigh a kilogram. The leaves are heart-shaped and alternate, the flowers small and white in loose panicles, and the whole plant dies back to the ground each winter.
It is now placed in the genus Reynoutria, though the older name Polygonum multiflorum is still on every packet. Cultivation is concentrated in Guangdong, Guizhou and Sichuan, and the root is lifted at three or four years, sliced and dried. The tuber is dark brown outside and reddish within, and it is sliced thick for drying because thin slices crumble.
Science & Biotechnology
The marker compound is a stilbene glucoside, 2,3,5,4′-tetrahydroxystilbene-2-O-β-D-glucoside, known simply as TSG. The root also contains anthraquinones, chiefly emodin and physcion, and it is those that make the raw root a laxative.
Processing is a chemical step, not a ritual. Repeated steaming with black bean decoction, traditionally nine times, hydrolyses the anthraquinone glycosides and lowers the free emodin, which reduces the purgative effect. The safety story is more serious: liver injury from he shou wu has been reported since 2006, the Chinese regulator issued a warning in 2014 requiring liver monitoring, and a 2019 study associated susceptibility with HLA-B*35:01. The processed root is also used in hair preparations, a use that has no supporting trial and carries the same liver caution.
Uses & Benefits
Processed root is used in Chinese medicine for what is described as deficiency of kidney and liver, with hair loss and lower back weakness as the usual complaints. The raw root is a purgative and is a different medicine.
Dose is six to twelve grams, and courses are traditionally short. Anyone with existing liver disease, anyone taking another hepatotoxic drug, and anyone pregnant should not take it. Symptoms to watch for are nausea, dark urine and jaundice, and the liver enzymes should be checked if it is used for more than a few weeks. Because the raw and processed roots behave so differently, packets should state which one they contain.
Growing from Seed
Seed germinates without much fuss at 20°C in spring, but cuttings and root divisions are quicker and give a uniform plant. The vine needs a strong trellis: growth is vigorous enough to smother a small tree in one season.
Deep, loose soil gives the tuber room to swell, and a mulch of compost keeps the shoulders covered. Lift at three to four years in late autumn, replant the small roots, and dry the rest in slices. The species is invasive outside its range, spreading by rhizome fragments along watercourses, so garden waste should never be dumped. Seed can also be sown in autumn where winters are cold enough to break dormancy naturally.
Our Take
A vigorous vine with a real medicine and a real liver risk attached; grow it behind a fence and use it only with a reason and a liver test.
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