Fo-ti (He shou wu): the traditional tonic with a real hepatotoxicity signal

← Back to articles

Fo-ti — the dried root of Polygonum multiflorum, sold under names like He shou wu, fleeceflower, or shou wu pian — has a documented and reproducible hepatotoxicity signal across hundreds of reported cases and regulatory action from multiple national agencies. The hair-darkening and longevity claims that drive the supplement market are essentially unsupported by controlled human data, while the liver-harm signal is one of the better-characterized in herbal hepatotoxicity. This is a case where the marketing promise is weak and the safety case against it is strong.

What the Herb Actually Is

Polygonum multiflorum root has been used in traditional Chinese medicine for centuries. Two preparations exist: raw root (sheng he shou wu) and processed root (zhi he shou wu) prepared by stewing with black-bean broth. The processing reduces anthraquinone glycoside content. Both preparations contain stilbene glycosides (2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucoside, abbreviated TSG), emodin and other anthraquinones, and tannins. The compound chemistry matters because the constituents most strongly implicated in liver injury — the anthraquinones and, in mechanistic work, TSG — are present at different levels depending on how the root was prepared.

The Hepatotoxicity Case Record

By the mid-2010s, Chinese adverse-drug-reaction monitoring had collected several hundred case reports of fo-ti-associated liver injury, and the herb appears repeatedly in reviews of traditional-Chinese-medicine-induced liver injury alongside other well-known hepatotoxic botanicals. The typical picture is a hepatocellular injury pattern, with onset commonly weeks to a few months after starting, transaminases rising to many times the upper limit of normal, and recovery in most cases after discontinuation — but occasional progression to acute liver failure, transplantation, or death. The signal is consistent enough that the UK, Australian, and several East Asian regulators have acted on it. Because the injury is delayed and the product is "natural," patients and clinicians frequently fail to connect the two.

Mechanism and Idiosyncrasy

The hepatotoxicity is idiosyncratic — it does not happen in everyone — and the strongest human work points to an immune-mediated mechanism rather than simple dose-dependent toxicity. A genetic susceptibility marker, the HLA-B*35:01 allele, has been identified: in a prospective cohort, carriers had a markedly higher rate of transaminase elevation on fo-ti than non-carriers, and the allele was dramatically over-represented among confirmed cases. Clinical and experimental data further implicate immune perturbation, with the pro-inflammatory cytokine TNF-α emerging as a correlate of susceptibility. Mechanistically, anthraquinones and TSG appear to act on already "primed" or inflamed livers. Raw root carries a higher anthraquinone load and a higher case rate; processed root reduces but does not eliminate the signal.

What the Efficacy Data Show

Despite extensive traditional use for hair color, longevity, and "kidney essence," randomized controlled human evidence for any of these indications is essentially absent. A handful of small Chinese trials report subjective improvements, but methodology is generally poor and publication is heavily skewed. The TSG fraction has been investigated as a candidate for Alzheimer's and Parkinson's disease in animal models without translation to humans. In short, there is no controlled human outcome that would justify accepting a recognized hepatotoxicity risk.

Drug Interactions

Fo-ti is a moderate CYP3A4 inhibitor in laboratory assays and a reported precipitant of warfarin-associated INR fluctuations. Concurrent use with hepatically cleared drugs — statins, calcineurin inhibitors, many antibiotics — widens the risk window for liver injury even at lower exposures. Concurrent acetaminophen at doses near the toxic threshold is particularly risky, since both insult the same organ.

Regulatory Status and Safer Alternatives

The UK restricted Polygonum multiflorum-containing products after a cluster of liver-injury reports; Australian and several East Asian authorities require warnings on labeling. In the US it remains legal as a dietary supplement, with no warning-labeling requirement outside voluntary GMP standards, and the FDA has issued adverse-event correspondence rather than a formal market action. Anyone using fo-ti should at minimum check baseline liver function and repeat it at 4–8 weeks, and should treat concurrent hepatically active drugs as a contraindication. If the goal is general "liver support," the irony is that fo-ti is a liver risk, not a liver tonic — and the supplements people actually reach for in that space, such as milk thistle (silymarin), N-acetylcysteine, curcumin, and resveratrol, carry a far better safety profile (though their own efficacy claims are modest). Note that some botanicals marketed as gentle, such as kava, carry their own hepatotoxicity signal — "natural" is not a safety category.