Is Kava Safe?

Kava is a plant that grows in the western Pacific. It was traditionally prepared as a drink and used for its psychoactive properties, including sedation, relaxation, and relief of anxiety. It is intoxicating but not addictive.

It has become a popular supplement in the US, used to treat anxiety, depression, insomnia, stress, and menopausal symptoms. It has also been suspected of killing quite a few people.

The AAFP Recommends Kava

In August 2007 American Family Physician, the journal of the American Academy of Family Physicians, published an article on “Herbal and Dietary Supplements for Treatment of Anxiety Disorders.”

They concluded that

St. John’s wort, valerian, and omega-3 fatty acids have little therapeutic value for anxiety disorders, and their use should be discouraged.

But they recommended kava. Not only that, they gave it the highest quality-of-evidence rating: A. They said,

Short-term use of kava is recommended for patients with mild to moderate anxiety disorders who are not using alcohol or taking other medicines metabolized by the liver, but who wish to use “natural” remedies.

In an accompanying table, they admitted that “Cases of liver toxicity have been reported, some requiring organ transplants; kava preparations withdrawn from the market in many countries; the FDA issued an advisory” – but they more or less dismissed these warnings by adding “later, research SUGGESTED [my emphasis] that nonstandard inclusion of the kava plant’s bark in kava preparations increased toxicity level.” And they went on to say, “Researchers concluded that liver toxicity is rare and idiosyncratic, with the majority of reported cases resulting from the combination of kava with other hepato-active agents; the benefits of kava seem to outweigh its risks.”

Not everyone reads the details in tables. In the body of the article, the text only said, “side effects reported with long-term use include a reversible skin rash or lesion and a yellow tint to the skin, but these reports have not been routine. Despite the absence of long-term data on safety and effectiveness, the evidence shows that short-term use (i.e., up to 24 weeks) can lead to small improvements in generalized anxiety, and that short-term risks do not outweigh the benefits.”

Other Sources Disagree

The Natural Medicines Comprehensive Database doesn’t give kava an “A” rating. It doesn’t rate it as effective or even probably effective. It only gives it a “possibly effective” rating. While the majority of evidence shows it is superior to placebo, there is contradictory evidence showing it is not superior to placebo. And the clinical studies used an extract that was more than twice as concentrated as most commercially available products.

It also rates kava as “possibly unsafe:”

There are at least 68 reported cases of liver toxicity following kava use. The use of kava for as little as one to three months has resulted in the need for liver transplants, and even death. Kava has been banned from the market in Switzerland, Germany, Canada, and several other countries are considering similar action. Some patients may be more at risk than others. Patients who are “poor metabolizers” might be at greatest risk, but this has not been verified. Until more is known, tell patients to avoid kava. Recommend routine liver function tests for patients who continue to use kava.

It particularly warns against use in pregnancy or lactation.

It also gives a long list of side effects, from minor gastrointestinal symptoms to serious reactions and kava dermopathy. Kava has been associated with severe, rapidly progressive Parkinson’s disease. It has caused erratic driving resulting in DUI citations. It may cause extrapyramidal side effects (involuntary movements). Liver toxicity may occur in kava users after a single occasion of alcohol consumption.

It lists numerous drug interactions. Kava significantly inhibits several cytochromes. It points out that Up to 10% of people of European descent have a genetic deficiency of CYP2D6, a deficiency that has not been found in Pacific Islanders.

In The Desktop Guide to Complementary and Alternative Medicine: An Evidence-Based Approach, Edzard Ernst and his co-authors cite serious safety concerns and recommend that if kava is taken it should be short term and under close medical observation.

The AAFP Ignores Me

Immediately after the article was published, I wrote a letter to the editor. I expressed the concerns above and said the article unfairly minimized the potential dangers of kava and should at least have reminded physicians that under the Diet Supplement Health and Education Act of 1994 these products are not regulated to insure consistency and purity.

They didn’t publish my letter.

The AAFP Has Second Thoughts

In August 2008 (a year later), the journal published a letter to the editor from the authors of the original article. It said in part,

The FDA warnings in 2002 are still in effect and are echoed widely by respected sources such as the Natural Medicines Comprehensive Database, the National Center for Complementary and Alternative Medicine, and the NSRC research collaboration. Given the lack of regulation for supplements and the absence of clear indicators of who is at risk for toxic reactions, cautionary statements continue to be justified. Physicians who supervise patients taking kava for the treatment of GAD should take care to avoid the following: (1) high dosages (more than 300 mg per day); (2) combining kava with hepatoactive agents; (3) using non-root preparations; and (4) exposure for longer than 24 weeks. Use of WS1490 standardized kava extract is also recommended. If these safety precautions are followed, kava can be appropriate therapy for selected patients diagnosed with GAD

Is There a Double Standard?

A friend told me that most of the recent liver transplant cases he’s been involved in were on patients who had been using kava. I wonder if all the cases of liver toxicity associated with kava are being reported in the medical literature. I wonder if some patients with liver toxicity neglect to tell their doctors they have used kava. I wonder: if 68 cases of liver toxicity, transplants and death were reported in association with a prescription drug, would it still be on the market?

Posted in: Herbs & Supplements

Leave a Comment (15) ↓

15 thoughts on “Is Kava Safe?

  1. qetzal says:

    I recently encountered another case of a presumably respectable medical association recommending a CAM treatment based on what seems like clearly inadequate evidence. It came up in another on-line forum, where an internist claimed that lavender aromatherapy (by footbath or nebulizer) was “more effective scientifically” than approved drugs for dementia. When pressed to support that claim, he cited a published consensus statement on clinical practice with anti-dementia drugs from the British Association for Psychopharmacology.

    In the abstract, the authors claim:

    There is type 1a evidence for cholinesterase inhibitors (donepezil, rivastigmine and galantamine) for mild to moderate Alzheimer’s disease; memantine for moderate to severe Alzheimer’s disease; and for the use of bright light therapy and aromatherapy.

    They repeat the claim about aromatherapy three times in the body of the article, repeatedly giving it both the highest level of evidence rating (1a: evidence obtained from meta-analysis of randomized controlled trials) and the highest grade of recommendation (A).

    Yet, when you read carefully, they provide only one citation to support this recommendation – to an editorial (!) written by the same first author as the consensus statement.

    That editorial cites 3 studies. Two involved lavender oil, and one involved lemon balm. One of the lavender studies (Smallwood et al.; refer to the linked editorial above for full citation) was so statistically flawed as to be worthless, IMO. (I won’t go into details, in the interest of brevity.) In any case, it claimed that aromatherapy plus massage was better than aromatherapy plus conversation. So even if you accepted their stats, any effect was apparently due to massage, not aromatherapy!.

    The second lavender study (Holmes et al.) was better, and reported an effect via inhalation at p = 0.02, but tested only 15 patients. The lemon balm study (Ballard et al.) appears to be the best, with n = 72 and p less than 0.0001 (via topical applicaiton). It also claims to be double blind, although I’m not sure how that can be true if lemon balm has an aroma and the placebo (sunflower oil) does not.

    Apparently those three studies, cited in an editorial, were sufficient for the BAP to claim aromatherapy works for dementia. What I’d like to know is, since when does an editorial qualify as a meta-analysis? And since when are two small positive studies on two different agents administered by two different routes adequate evidence for a Grade A recommendation?

    Is the BAP considered a respectable association in its field? If so, why would they endorse a treatment based on such limited data?

    Double standard indeed!

    (To be clear, I’m not arguing that aromatherapy doesn’t or can’t work. In fact, it seems to me quite possible that the right aromatherapy might indeed work for some cognitive or emotional indications. I’m simply objecting to claims that it does work based on such limited evidence.

    Apologies for the length.)

  2. Calli Arcale says:

    I wonder if some patients with liver toxicity neglect to tell their doctors they have used kava.

    Given that kava is now available as an additive in various beverages, sold not in drugstores but in grocery stores alongside the light beers, I suspect that a great many kava users do not think to mention it. After all, if it’s in a drink, it’s not a drug . . . is it?

    That’s a rhetorical question, of course. It’s a drug every bit as much as alcohol is. It’s just not being sold as one in that case, and users probably won’t realize that they shouldn’t drink alcohol with it — or take drugs like acetominophen.

  3. DBonez says:

    Post: “A friend told me that most of the recent liver transplant cases he’s been involved in were on patients who had been using kava. I wonder if all the cases of liver toxicity associated with kava are being reported in the medical literature. I wonder if some patients with liver toxicity neglect to tell their doctors they have used kava.”

    I wonder home many of those liver toxicity cases were male, East Indian, and/or Pacific Islander?

    I’m a white-bread American guy, but my wife is of East Indian descent from Fiji. At virtually every celebration I’ve been to with her friends and family, the Indian/Fijian men indulge in a kava drink made by pressing kava roots through a cloth with water. It makes a thin, brown liquid much like runny chocolate milk. It, along with beer and liquor, are a staple at virtually every gathering, party, barbeque, or birthday. Every event I’ve been to, there are women in the kitchen cooking, and men sitting in the garage drinking kava and glasses of Scotch; lots of kava and lots of Scotch. I don’t mean to sound sexist, but that’s just how they do it. I tried some kava drink once and it was horrible, bitter, and dirty tasting. My tongue went numb and my throat burned and I was reminded of being 15 and trying Vodka for the first time. The skeptic part of my brain along with my basic survival instincts said this stuff was bad, that it shouldn’t be taken internally, and that it should be a controlled substance. I forced a smile and raised my glass in approval and later ditched my drink into a planter. I’ve not gone near kava since, nor will I.

    I guess I was right about the controlled-substance part of my assessment. I could try to warn the guys about their dangerous mix, but I don’t think it would go over very well. Their kava drink has a long history spanning back many generations. Maybe if one of them ends up on a liver transplant list, I’ll be sure to tell the staff about their kava use.

  4. Peter Hansen says:

    This is the same AAFP that gave out health guides in 2005. In it, there was an advertisment for EAR CANDLES!

    My complaint to them remained unanswered. At least the following year there were no ads for ear candles. My only complaint was a pro-supplement article written by Julia VanTine-Reichardt, a freelance writer. Amazingly, the article was sandwiched around an ad for USP (US Pharmacopeia) !!!

    Apparently, this writer doesn’t read the info on her own recommendation list:

    she says “A combination of antioxidants has been found to slow the progression of age-related macular degeneration…”

    yet the NIH site references this article


    The role of antioxidant supplements in the prevention of AMD or in slowing progression of AMD for those with the early stages of the disease has not been adequately answered in randomized controlled trials. Observational studies have returned conflicting results. It is possible that there are long-term risks in high levels of supplementation of specific antioxidants and minerals.



  5. Harriet Hall says:

    I’m glad I didn’t see the health guide with the ear candle ad – I probably would have had a stroke!

    Re: antioxidant supplements for macular degeneration – the evidence is easily misunderstood. The supplements have been shown to slow the progression of established macular degeneration, but they haven’t been shown to prevent it or to help in the early stages.

  6. Jules says:

    So 68 people die of liver failure after taking kava and it must be banned, because of course they didn’t have any prior liver damage from rampant alcohol use, nor did they take a ton of it all at once rather than the way it’s traditionall consumed. Because we can always assume that people who try kava aren’t just looking for a better high, and won’t be disappointed when they just get mellow, and see if taking more won’t give them a bigger badder high.

    Let me play the devil’s advocate for a minute: we all acknowledge that different strains of plants, different sources, and different preparations can all lead to a mishmash of god-only-knows-what chemicals floating around in your kava drink. We also know that in the West, booze is easy to get a hold of. I have no idea what sort of rotgut is sold in the societies where kava is traditionally consumed, but given that alcohol is banned by Islam from many of those societies and that Asians generally don’t tolerate alcohol nearly as well as Caucasians, we can probably assume that traditionally kava was drunk as kava and sans booze.

    Kava doesn’t grow in the continental US, nor the Continent, so it has to be imported–sketchy factor #1: what’s actually being imported? Most people in the US grow up with alcohol, whether it’s the daily glass with their meal or a six-pack on the weekends (or daily)–sketchy factor #2: how much liver damage did these people start out with? And lastly–you mentioned yourself, the genetic differences between the people from societies where kava is part and parcel of their daily lives and the ones for whom kava is either a shortcut to a great head trip or a calming agent obviously has some ramifications for safety.

    I point these out, not to say that kava is safe–I’m wary of most psychotropics, given that I’m insanely sensitive to them–but that the traditional versus Westernized (bastardized?) usage of the plant, as well as social circumstances, are important to consider when trying to decide whether kava is “safe”.

    I should also submit that banning what’s largely a recreational drug is a virtual guarantee that it’s popularity will increase. And if full disclosure of the risks of death and dying are not deterring people from smoking, well, good luck with kava…

  7. qetzal says:


    I agree that how kava is used will certainly affect whether it’s sufficiently safe. But I think that’s mostly beside the point.

    For me, the biggest take-home messages of Dr. Hall’s posts were:

    1) We don’t know whether and how kava can be taken safely.

    2) There is substantial, if inconclusive, evidence that kava may be very dangerous or fatal under some circumstances.

    3) In spite of (1) and (2), AAFP gives a Grade A recommendation in favor of short term kava use!

    That’s so irresponsible as to be almost criminally negligent! (Caveat: IANAL).

    As to whether kava should be banned today, I don’t know. Yes, that could easily shine a spotlight on it, causing more people to want to try it. But if (2) above turns out to be true, it should still be banned, or at least more carefully regulated. That should greatly reduce the chance of someone being harmed by it without realizing the danger.

    Then, if some people are prompted to try it in spite of the ban, so be it. At least they had some warning.

  8. Harriet Hall says:


    Wow! You really have a chip on your shoulder. I didn’t recommend that kava be banned.

    My article was focused on a specific medical use of kava: to treat anxiety. Recreational use is another question entirely.

    Tobacco and alcohol do lots more harm than kava, but we put warning statements on the products. Some kava users may not be aware that there is any concern about possible liver damage: don’t they have the right to know, whether it is a verified risk or simply a suspicion?

    You misread what I wrote: it was “68 cases of liver toxicity, transplants and death” not 68 fatalities. If a similar number of reports were associated with a prescription medication, people would likely be calling for it to be taken off the market. That action would not be justified without putting the risks into perspective with the benefits.

    In the case of kava, the benefits for treating anxiety are not clearcut; the NMCD rates it only as “possibly” effective. Considering that and considering the safety concerns, the original AFP article was unfairly slanted, and even its own authors recognized that and issued a corrective.

  9. delaneypa says:

    As an practicing FP myself, I have never found the AAFP journal much use, in American Family Physician, they seem to written at a medical student level. Given that 1500 medical articles are published daily, there are always plenty of review articles avalable on just about any topic. Indeed, more up-to-date references are available in the Web.

    I really was soured on the AAFP when they published in the Family Practice Management journal the following article in summer ’07:

    Are You Ready to Discuss Complementary and Alternative Medicine? If you haven’t been communicating openly about these therapies with your patients, you may be missing a valuable opportunity.

    The article did not bother with details about whether SCAM actually works, it was just presented as a great opportunity to expand one’s practice by identifying and catering to True Believers.

    Perhaps more enlightening were the subsequent letters to the editor:

  10. Jules says:

    @ Harriet:

    It just seems that the issue of recreational versus medicinal use is a very fuzzy one. Someone with social anxiety might take it when he goes to parties–is that recreational, or medicinal use?

    As for misreading: sorry–from here it sounded like there were 68 people who got liver failure, transplants, and then died in spite of the transplant.

    I wholeheartedly agree that there should be warning labels on kava products, though.

  11. Harriet Hall says:

    Jules said,

    “It just seems that the issue of recreational versus medicinal use is a very fuzzy one. Someone with social anxiety might take it when he goes to parties–is that recreational, or medicinal use?”

    The same might be said for alcohol, but as far as I know medical authorities are not recommending alcohol as a treatment for anxiety. And information about the risks of alcohol is widely available.

  12. Harriet Hall says:


    I submit that you and I and other like-minded family physicians share the blame for any infiltration of nonscientific CAM treatments into AAFP publications. We have not complained loudly enough. CAM supporters are more likely to be vocal activists.

    I write letters to the editor that don’t get published and that seem to be a waste of time, but if enough readers did the same, the editors would have to pay attention.

    There is power in numbers. As Arlo Guthrie said about singing “Alice’s Restaurant” to avoid the draft:
    “You know, if one person, just one person does it they may think he’s really sick and they won’t take him. And if two people, two people do it, in harmony, they may think they’re both faggots and they won’t take either of them. And three people do it, three, can you imagine, three people walking in singin a bar of Alice’s Restaurant and walking out. They may think it’s an organization. And can you, can you imagine fifty people a day, I said fifty people a day walking in singin a bar of Alice’s Restaurant and walking out. And friends they may thinks it’s a movement.”

  13. qetzal says:

    Alice’s Restaurant! Excellent! Thanks for making me smile, Dr. Hall!

    So, is there a song we can sing to join the Science-Based Medicine Anti-CAM-Massacre Movement? I can do (bad) harmony. Anybody play guitar?

  14. Harriet Hall says:

    How about a parody of “You can get anything you want at Alice’s Restaurant (exceptin’ Alice)”

    Something like: “You can get anything you want at CAM’s Magic Store (except it won’t work)”

    Or we could use “Lily the Pink,” a venerable folk song about Lydia Pinkham’s Vegetable Compound – see and click on the free MP3 link to hear it performed.

    I can strum chords on the guitar. Do you think they would let us perform at the next AAFP or AMA convention? :-)

  15. delaneypa says:

    Dr. Hall,

    Unfortunately I didn’t catch the above article until a few months after it was published, too late in the news cycle to write a suitably vitriolic letter to the editor. Apparently, letters to the editor will only be entertained within a 1-2 month window after article publication. Since I (like most physicians) get about 15 journals a week, picking out SCAM articles can be like finding a needle in a haystack.

    But since the AAFP sends table of contents by email, it is possible to set up an email filter to “flag” such articles, and perhaps even forward them automatically to like-minded colleagues motivated enough to write a letter.

Comments are closed.