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Threats to ashwagandha safety: How do we respond to new reports of liver damage?

  • Simon Mills
    Simon Mills

    I am a Cambridge medical sciences graduate and have been a herbal practitioner in Exeter since 1977. In that time I have led the main professional and trade organizations for herbal medicine in the UK and served on Government and House of Lords committees. I have written standard textbooks used by herbal practitioners around the world, including with Professor Kerry Bone from Australia.

    I was involved in academic work for many years, co-founding the University of Exeter pioneering Centre for Complementary Health Studies in 1987 (where we built a complementary research and postgraduate teaching programme from scratch), then at Peninsula the first integrated health course at a UK medical school, and the first Masters degree in herbal medicine in the USA, at the Maryland University of Integrative Health.

    I am particularly fascinated by the insights we can distill from the millions of intelligent people who over many centuries needed plants to survive. Mostly I want to learn and share the old skills, to experience healing plants as characters, that can help us fend off ill health. My passion for offering people tools to look after themselves and their families has led me to work with the founders of the College of Medicine on pioneering national self care and social prescribing projects. I am now the College Self Care Lead and also Herbal Strategist at Pukka Herbs.

    Listen to our Herbcast podcast with Simon Mills as the host.

  • 25:32 reading time (ish)
  • Safety

Evidence suggests that one of our most widely prescribed herbs, ashwagandha, poses a risk to liver health. Withanolides have been implicated in hepatic injury and investigations have found adulteration of root supplies by withanolide-rich leaves. Simon Mills discusses findings and how we may responsibly engage with this information ‚ÄĒ How do we protect our patients? How do we protect the use of this herb in our practice?

Background and summary

Threats to ashwagandha safety How do we respond to new reports of liver damage

The herbal sector has for decades been exposed to suspicions and some evidence that herbal remedies might cause liver problems, challenges that we have found hard to refute. Liver injury is most often not immediately apparent and so traditional experience is not a strong assurance that this does not happen. Already, because safety arguments have been ineffective, kava-kava has been widely banned around the world for this association, and variously black cohosh, germander, chaparral and shou wu (Polygonum multiflorum) have been seriously implicated; comfrey, ragworts and borage are very widely restricted for their pyrrolizidine alkaloids; now even fennel is threatened, and there is new evidence implicating curcumin-rich extracts of turmeric (1). Indeed the relative incidence of herb-related reports relative to conventional medicines is rising, perhaps as more attention is being paid to this possibility (2).

Ashwagandha (Withania somnifera) is one of the most widely used remedies in the herbalist‚Äôs dispensary, so new challenges to its safety are concerning. Since 2017 a cluster of reports, from the USA, Iceland and elsewhere, have suggested that it may be implicated in cases of liver injury. Now for the first time, cases have emerged from India, the land of its origin and most widespread use. In the most challenging report so far, a thorough review of cases obtained from just three Indian hospitals has identified serious adverse effects on liver function, including death, most of which were ‚Äėprobably‚Äô associated with taking ashwagandha. Even allowing for the declared bias against Ayurvedic medicine by the lead author of the paper, these findings could signal a significantly wider health issue, not least in the likely spread of the message that ashwagandha is dangerous for the liver. 

In this review of the evidence, we look closely at these reports, and consider some of the wider issues linked to liver injury following the intake of herbs. Three recommendations then emerge for the practitioner who wishes to use ashwagandha with minimum risk and proactively to engage with any threat to its use.

  1. Ensure supplies of ashwagandha are assured as root only, without added leaf, and otherwise to avoid high withanolide products.
  2. Avoid prescribing ashwagandha in patients with severe liver disease such as cirrhosis or liver cancer.
  3. Avoid ashwagandha if the patient is regularly taking paracetamol (Tylenol).
Simon Mills

I am a Cambridge medical sciences graduate and have been a herbal practitioner in Exeter since 1977. In that time I have led the main professional and trade organizations for herbal medicine in the... Read more

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