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Herbal medicines fail test

October 4th, 2007 · 30 Comments

A paper published in the Postgraduate Medical Journal, October 2007, has been reported widely. In the same issue there was a commentary by Edzard Ernst. They show the astonishingly poor evidence than herbal treatments work, despite the fact that they have been around for thousands of years. They looked at 1330 published trials on herbal medicines and found 3 (yes three) that stood up to scrutiny, Of those three, two were negative and one indecisive

Red clover, Derwentwater.

The Journal (published by the BMJ group) again issued the press release before the paper was available -utterly irresponsible behaviour. But the papers are available here, so I have posted the reprints so you can read them yourself.


A systematic review of randomised clinical trials of individualised herbal medicine in any indication, R. Guo, P. H. Canter, and E. Ernst, Postgrad Med J 83: 633-637 [Get the reprint]


Herbal medicine: buy one get two free, E. Ernst, Postgrad Med J 83: 615-617 [get the reprint]

Grab the reprints before I am told to remove them.

The paper says

“Systematic searches of electronic databases and contacting
experts and professional bodies in the field resulted in the
location of only three randomised clinical trials of individualised
herbal medicine. It should be stressed that professional
bodies representing the interests of different practitioner
factions from around the world were unable to contribute any
more studies than this. In view of the long history and
widespread use of medical herbalism, Chinese herbal medicine
and Ayurvedic herbal medicine in many and diverse indications,
this should be a cause for concern. It indicates that
individualised herbal medicine has an extremely sparse
evidence base and that there is no convincing evidence
supporting its use in any indication.”

The National Institute of Medical Herbalists says

“More and more people are turning to herbal medicine as a kinder alternative to mainstream medicine, with its over reliance on pharmaceutical products.”

Wrong. Herbal medicines are pharmaceutical products. They are just unstandardised, and often impure and contaminated, pharmaceutical products.

In the Guardian we find Ann Walker quoted thus.

“Ann Walker, director of the British Herbal Medicines Association, insisted that most herbalists were well-trained and knew when to refer patients. She said herbalists took a three or four-year degree course before accreditation.

She acknowledged the lack of proof of efficacy for individualised herbal medicine. “The evidence is scanty because the studies have only recently been started,” she said. This did not mean there was no efficacy.”

Just a thought: shouldn’t you have some evidence that they work before you start selling them? These things have been around for thousands of years but the “studies have only recently been started”. You couldn’t make it up. You can’t have a high level of training if there is no evidence. The paucity of trials makes it very hard to know how you can fill up a three or four year course with anything but idle speculations. Universities should not being giving degrees in idle speculation.

Quote of the day. . Of all the pathetic defences offered by herbalists, this one, quoted in the Daily Mail, is my favourite.

“Jane Gray, of the National Institute of Medical Herbalists, said: “We would challenge the conclusions reached by this study based on such little data.”

“We want more research, but we’re all in private practice and cannot afford to stop earning to run a trial over several months.”

The fact that there is “so little data” is the conclusion. And perish the thought that a herbalist should “stop earning” just in order to find out whether what they are selling does any good.

The regulation scam

Alison Denham, speaking for the National Institute of Medical Herbalists, is quoted as saying

“But there are certainly issues around the expertise of practitioners which need to be addressed, and we look forward to government regulation which imposes a high standard of training on anyone who wants to register.”

Like all forms of alternative medicine, herbalists are desperate for government “regulation” because they know it gives the appearance of official approval without requiring them to show that they can do the slightest good.

Reports on this paper

The BBC web site: “Tailored herbal medicine ‘futile'”.

The Guardian report, by Sarah Boseley, is pretty good.  “Herbalists’ cocktails may do more harm than good, say researchers.”

  • Call for individualised remedies to be banned
  • Little evidence to support claims of efficacy

The Times has another excellent report by Nigel Hawkes. “High street herbalists can offer no evidence that their remedies work”

The Independent. “Natural medicine on trial: The trouble with herbs. Traditional herbal remedies have never been more fashionable: sales have almost doubled in eight years. There’s just one problem: science suggests that they don’t work.”. This time Jeremy Laurance got the headline right (unlike the acupuncture piece). But where did that list of “Herbal remedies that work” at the end come from? Had he checked the Cochrane Reviews? I think not.

The Daily Mail. “Herb cures that ‘do you more harm than good’ “. Pretty good report. specially for the Daily Mail.

The Scotsman. “A natural cure?” Lyndsay Moss. Sadly, and unusually, this is the only really poor report. Just look at the end of it.

Postscript

On Saturday morning (6 October) I did an interview on the Dublin radio station, Newstalk. The host, Brendan O’Brien spoke also to Mary Plunkett, from the Professional Register of Traditional Chinese Medicine. She assured us that that, although there may be no evidence that it works published in the West, there were lots written in Chinese. What a pity that I had not yet read Ben Goldacre’s column, on this week’s bad news for herbalists. He cited a reference that was new to me.

You can read the abstract here. [download pdf]. The paper, by Vickers, Niraj, Goyal, Harland and Rees (1998, Controlled Clinical Trials, 19, 159-166) has the title “Do Certain Countries Produce Only Positive Results? A Systematic Review of Controlled Trials”. The conclusion is riveting.

“In the study of acupuncture trials, 252 of 1085 abstracts met the inclusion criteria. Research conducted in certain countries was uniformly favorable to acupuncture; all trials originating in China, Japan, Hong Kong, and Taiwan were positive, as were 10 out of 11 of those published in Russia/USSR. In studies that examined interventions other than acupuncture, 405 of 1100 abstracts met the inclusion criteria. Of trials published in England, 75% gave the test treatment as superior to control. The results for China, Japan, Russia/USSR, and Taiwan were 99%, 89%, 97%, and 95%, respectively. No trial published in China or Russia/USSR found a test treatment to be ineffective.”

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Tags: Anti-science · CAM · Dangerous advice · evidence · herbalism · Universities

30 responses so far ↓

  • 1 Claire // Oct 4, 2007 at 13:28

    The person at the Scotsman responsible for this:
    “AND THE HERBS THAT MAY DO SOME GOOD

    ECHINACEA
    Made from the plant Echinacea angustifolia, this herbal medicine is believed to boost the immune system, meaning it should make people more resistant to infections such as coughs and colds. In June, researchers in the United States said taking echinacea could more than halve the risk of catching a common cold, but previous studies had shown no beneficial effect.

    CAMOMILE

    This herb, popular in tea, is commonly recommended for the treatment of stress. Research in 2005 also found that drinking camomile tea could fight a cold and banish menstrual cramps.

    Herbalists may also recommend it for helping the digestive system and fighting allergies. …”

    might like to have a look here, esp re echinacea in asthma: http://www.aaaai.org/patients/advocate/2006/summer/herbal.asp ‘Risks of herbal medicine for the allergy patient’. The AAAAI (www.aaaai.org) provides huge quantities of evidence based information pm allergy and asthma, including in its AADMC centre, which review current literature, news and has an ‘ask the expert’ area: http://www.aaaai.org/aadmc/

  • 2 Slartibartfast // Oct 4, 2007 at 13:52

    I have to wonder if the Scotsman journalist actually read Canter and Ernst’s paper. The paper is about individualised treatment, not specific plants. I am though a little cheered by the more sensible reader comments posted.

  • 3 David Colquhoun // Oct 4, 2007 at 15:24

    Tnanks Claire, And echinacea cures a cold in seven days, when otherwise it might have lasted a week, The Cochrane Review is here.

  • 4 coracle // Oct 4, 2007 at 17:37

    Thanks for posting the articles, I’m looking forward to doing some reading.

  • 5 norfolk // Oct 28, 2007 at 01:09

    Here’s an idea – since the herbal and homeopathic remedies are so blasted expensive, and cost nothing to make why not require a portion of each sale to go towards testing the efficacy?

    After all, the big drug companies are always saying that they need to recoup their testing costs, which are actually only about 10% of the advertising costs.

  • 6 Anti-D // Nov 6, 2007 at 17:21

    Dear High Priest of Medical Science,

    Under the heading ‘The Regulation Scam’ you write, ‘Like all forms of alternative medicine, herbalists are desperate for government “regulation” because they know it gives the appearance of official approval without requiring them to show that they can do the slightest good’.

    You must believe you have preternatural insight into the minds of herbalists to write the above piece of nonsense. Let me pull the cork on this particular delusion: the majority of herbalists do NOT want government regulation. I won’t give you ammunition by giving the reasons for this position – I’m sure your very active imagination can dream up a number of nefarious motivations for this stance.

    I will, however, tell you a little bit more about the NIMH, which Alison Denham represents. It has a membership of a few thousand herbalists, of which no more than a couple of hundred make a living from herbal medicine. The issue of government regulation has NEVER been the subject of a vote by the membership. Government regulation is being driven by a few individuals within the NIMH for the spurious reason of placing herbal medicine on a sound legal footing. Herbalists already have protection under existing laws.

    Given the above, I think it is a waste of government time and money to push on with the regulation of such a small group of people.

  • 7 David Colquhoun // Nov 6, 2007 at 21:05

    Ah yes Anti-D, I see that you have been leaving the same sort of abusive comments on quackometer, under the name pluck-the-duck.

    Yes I was quite aware that there is a fringe of the most irresponsible CAM people who don’t want even the sort of toothless regulation that the government seems to like.

    May I suggest that you pursue that particular battle with the Prince of Wales, not with me?

  • 8 Anti-D // Nov 7, 2007 at 10:00

    You say abusive, I say combative…

    So if herbalists want regulation they’re desperate for official approval, but if they don’t, then they’re irresponsible. Bit of a double-bind I’d say. What is your grand vision for herbalists exactly?

    I am simply correcting the mis-information that your article peddles – I am not pursuing any battle with you. Anyhow, like you, the prince and the government are wont to believe that herbalists are a homogenous group – very useful in this age of standardisation. Death to diversity!

    I was simply correcting the

  • 9 jdc325 // Nov 7, 2007 at 11:37

    “What is your grand vision for herbalists exactly?”
    Speaking for myself, my grand vision for herbalists (and homeopaths and neutraceutical salesmen etc) would be for them to get proper jobs. At the very least, I expect pseudo-medical professionals to be properly regulated – preferably by independent watchdogs. Regulatory bodies need to have teeth – unlike NASH, SoH etc where figleaf codes of ethics are the order of the day.

  • 10 Anti-D // Nov 8, 2007 at 09:54

    So serial number jdc325 the mask slips – I thought this level of control-freakery went
    out of fashion in the 1940’s. Whatever next? The licensing of green grocers?

    For your information, my robotic friend, the regulation agenda is being pushed using evidence of poor quality and unsafe OTC herbal medicines. This may be news to you, but herbalists do not control or make money from the trade in OTC herbal products.

    Furthermore, one of the most frequently used pieces of evidence against herbal medicine is that of a slimming clinic in Belgium. That particular disaster was the result of medical doctors using a herb (Aristolochia) inappropriately and in combination with a cocktail of drugs. Were the doctors struck off for their incompetence? Of course not! They banned the herb (you couldn’t make it up, could you DC?).

    While we’re on the subject of ‘dangerous’ herbs, have you noticed that commonly sold OTC conventional medicines aspirin and paracetamol do not seem to have particularly good safety records. Last time I perused the MHRA Yellow Card Scheme database it showed 2840 reported ADRs for aspirin with 266 fatal outcomes, and 3088 reports for paracetamol with 187 fatal outcomes. I am not aware of any hand wringing over these statistics. However, the herb Kava Kava was banned in 2002 based on the assessment of just 68 ADR cases (3 fatal). Without exception, these cases were linked to poor quality and unsafe OTC products. Kava Kava has been traditionally prepared and used in Polynesia for hundreds of years and was used safely by traditional western herbalists in the UK for decades.

    In fact, practitioners of the western tradition of herbal medicine have an impeccable safety record and not a single example of incompetence or malpractice by a member of this tradition has ever been offered to substantiate the case for regulation.

    Anyway, I’m sure the above won’t make a blind bit of difference to you, but then again you’re probably just hardwired to be one-eyed.

  • 11 David Colquhoun // Nov 8, 2007 at 10:44

    I did wonder whether to delete anti-D’s last comment because of its abusiveness, I decided to leave it, because comments like this are perhaps the best advertisement that one can imagine for a rational approach to medicine.

  • 12 jdc325 // Nov 8, 2007 at 12:36

    I agree. Personally, I dislike the idea of censoring comments – even if they are slightly unpleasant in tone. I was disappointed by the decision Nadine Dorries made to stop publishing comments on her blog. I think in her case it was a failure to engage. Anyway, I find the idea of myself as a one-eyed, mask-wearing control-freak robot quite amusing.

    PS – I note Anti-D made reference to the ‘yellow card scheme’. One of my issues with Serious Complementary and Alternative Medicine is the lack of such schemes. Compare also the SoH controversy with GMC regulation of doctors.

  • 13 Anti-D // Nov 8, 2007 at 22:46

    Congratulations jdc325! My comments were meant to be amusing. As for you DC, your up-bringing must have been pretty sheltered to find my remarks abusive. Or perhaps the rarefied air of your ivory tower has made you more sensitive and slightly po-faced? Where I come from that kind of thing is called banter. But that is the problem with the net, it’s open to the hoi polloi, and coarse people like me post things without knowing the correct form of address.

    Your exchange above reminds me of two posh people talking about a servant as if he weren’t present in the room. I’ve nothing against posh people, but if you want to form a club then you should vet your members and charge an entrance fee.

    For your information jdc325, herbalists do report to the yellow card scheme, but maybe you didn’t notice the herbs listed on the MHRA yellow card website. And perhaps I imagined reporting an ADR to the scheme a couple of years ago, but then again, you’d probably rule that an ‘appropriation’ of an orthodox tool by an unauthorised, illegitimate pseudo-medical quack (by the way DC, that is called sarcasm, you may find it abusive so I apologise in advance).

    Finally, you talk about Nadine Dorries’s ‘failure to engage’ and then patently fail to do so yourselves – and they say Americans have no sense of irony…

  • 14 KB // Dec 8, 2007 at 00:52

    I’ve been reading several entries to this site with great joy and admiration, since I’m also very frustrated by the practices of spin, over-interpretation, selective omissions and innuendo demonstrated by bad scientists and their sponsors and marketers.
    However, this particular entry then left me first puzzled and then very disappointed. Since it seems to practice the very same spin etc., on what looks like a well-designed and serious study on a specific, minor, category of herbal medicine, the “individualised herbal medicine”, the results of which is very clearly not relevant for all or even for typical herbal medicine. This is clearly specified in the paper, but the word “individualised“ is mysteriously missing from all the explanatory text except in the direct quote. This spin or selective omission is particularly unjustifiable when it is revealed that the main message of both the press release and the commentary is that “individualised herbal medicine” is substantially different from two other categories of herbal medicines, and therefore does not have the same chance for efficacy.
    To make matters worse, the study is described as if the low ratio (3 out of 1330) of papers on good quality trials is a particular negative characteristic of herbal medicine literature, while of course this ratio is solely a function of the authors’ choices of search terms and selection criteria, and therefore it can be as small or large as you want, for pretty much any topic. If anything, a low ratio indicates a meticulous search effort. It is of course damning for the specific category “individualised herbal medicine” that only 3 properly designed trials have been published on it. But to present this as being even worse than it is, looks to me as innuendo rather than good science communication.

    Until now I have experienced 3 companies approaching me to test their herbal products for efficacy, because they believed an independent investigation would be to their advantage. Two of these 3 did show significant effects of the type the producers described in their marketing claims.
    While of course producers who are consciously lying about their products would not come forward to subject them to such testing, I have reason to believe these 3 producers and their 2 active products are not exceptionally unique. So when I saw the headline and introductory text for this entry, I knew immediately from my own research that it could not be a scientifically precise description of the situation, as it was indeed confirmed when reading the actual contents of the paper and the commentary.

    While I fully endorse all justified criticism of bad science, and recognise how astonishingly common it is, I don’t like to see it exaggerated into all-encompassing dismissals not substantiated by the references it is supposed to relate to. In order to criticise others, we must at the very least meet the same standards as we want them to follow.

    I have to declare an interest in this issue, since the research in one of the above mentioned products resulted in a patent, which until now has provided a personal share for me of £940 – without requiring me to do anything other than good science!

  • 15 LeeT // Dec 15, 2007 at 23:55

    Could some one explain to me what “individualised herbal medicine” is? Is it different to just plain herbal medicine?

    Secondly, my GP told me that St John’s Wort is a good way of treating minor to moderate depression? Have studies been done on SJW? If so is it one of the three studies mentioned above that stood up to scrutiny?

    Thanks!

  • 16 Ernst // Dec 17, 2007 at 12:27

    Individualised herbal medicine is the type practiced by all types of herbal practitioners worldwide. Patients are assessed according to certain criteria and then prescribed herbal mixtures which are tailor made according to these criteria. Thus 10 people with depression would get 10 different mixtures. This approach is very different from the standardised one where one herbal remedy is given for one condition, such as St John’s Wort for depression. The vast majority of placebo-controlled studies of St John’s Wort demonstrate effectiveness for mild to moderate depression.

  • 17 jdc325 // Dec 17, 2007 at 13:33

    The definition in the Guo/Canter/Ernst paper is that “patients receive tailored prescriptions comprising a mixture of herbs”. Apparently, most studies into herbal medicine have focussed on single herbs as standardised extracts.

    If I have it right, in the case of individualised herbal medicine your local herbalist might prescribe & sell you a mixture of home-grown Valerian and St John’s Wort and in the case of ‘non-individualised’ herbal medicine you might buy some factory-made St John’s Wort tablets (probably standardised to 0.3% hypericin) from your local supermarket or chemist.

  • 18 jdc325 // Dec 17, 2007 at 13:56

    Haha. I spent an hour reading about individualised herbal medicine and failed to refresh this page before I commented. I wouldn’t have bothered if I’d known the man himself was going to appear.

  • 19 superburger // Dec 17, 2007 at 15:00

    but, Ernst (for it is he?), do you agree that there is no special reason a priori why there does not exist an experiment that can test the claims made for each remedy – individualised or not?

  • 20 Dr Aust // Dec 17, 2007 at 17:57

    Lee, the wider point, as I see it, is that medical herbalists often respond to negative controlled trial results for standardized single agents – which is the way scientists naturally tend to approach testing things, as it is the method most likely to yield reliable answers as to whether plant extract X works for condition Y – by responding:

    “Aha, that is your (mainstream science) paradigm, we herbalists follow a different patient-specific health philosophy in which we tailor the remedy to the individual and their symptoms, therefore all your “negative result in trials of herbal remedies” is not a fair test of our healing modality.”

    – this is one of the lines our resident AltMed irritant Anti-D has run up the flagpole over in the other thread about “Should there be more alternative research”.

    Edzard Ernst is pointing out (notably in his editorial, link above) that the herbalists have never run a well-constructed trial of what they actually do (the individualized prescribing) either. Thus there is no evidence “individualized herbal therapy” does anything, whereas at least the “test standardized single remedy” approach the herbies routinely whinge about gets us a bit further forward – some remedies showing efficacy for some things, and others (rather a lot) showing none.

    The individualized remedies can of course be tested double-blind if you are careful enough about how you set up the experiment, as can homeopathic remedies. This is one of the things Ben Goldacre keeps pointing out in plain language in his Guardian column. Claiming that they can’t is just another of the obfuscation tactics used by the AltMed crew.

  • 21 Ernst // Dec 18, 2007 at 11:29

    The best proof for the argument that the individualized herbal medicine approach can be submitted to rigorous RCTs is the fact that 3 such studies are available (see our review). The 2 embarrassing points are 1) there is so very little evidence, 2) the little that does exist is not positive.

  • 22 LeeT // Dec 18, 2007 at 20:44

    This seem to be a common treatment pattern for alternative therapists: “Horrible doctors and psychiatrists will treat the disease whereas we will holistically cure the whole person.”

    They will often say we are all genetically unique blah, blah, blah.

    However, surely physiologically what unites is greater than what divides us in terms of genetic uniqueness. We are all water with a bit of fat thrown in!

    The individualised/person centred approach is all very expensive which is probably why is not available on the NHS.

    Is there any scientific basis to this approach or is it just about gratifying the ego of some one who can afford to pay for such treatment?

    PS Thanks for the above posts. A well known supplement salesman used to have a section on his website where his fans were invited to submit questions which would be answered in exchange for £10!

  • 23 workshop // Jan 29, 2008 at 02:35

    if there is so very little evidence,(that has been included in the paper) surely it may not be representative of the actual(probably much more complex)situation in day to day practice in herbal medicne newspaper reports seem and professor colquhons posts seem extremely dismissive,which seems to miss the point of the paper..surely more datais actually needed for an honest assessment of the subject?Although in an ideal world people would not use treatments which are not evidence based, we don’t live in that world.People do fundamentally irrational things every day,almost as soon as we wake up and start thinking in the morning!As long as people use herbal medicine in this way, and they do , and will continue to do so, then more honest reserch into attitudes and efficacy in herbal medicine are called for.

  • 24 David Colquhoun // Jan 29, 2008 at 06:12

    Workshop says more evidence is needed, and I don’t disagree. All I am saying is that, until that evidence is obtained, it remains sensible to be dismissive about the claims made for most herbal medicines. If good evidence is found, then I’ll change my mind. That is how science works.

  • 25 diana warwick // Feb 5, 2008 at 20:25

    Dear Dr. Colquhoun,

    I listened to your recent interview( Jan 27 2008) with Michael Enwright on the CBC Sunday Edition.
    I suffer from a disabling back problem. Bulging, ripped discs etc,,, and I couldn’t agree with you more heartily. I have tried literally everything. And acupuncture,,after 3 out of 5 visit, the kind doctor managed to make my back pain worse to the point I felt as if I was having a stroke!! Massage therapy rendered my unable to walk! And trying to do gentle exercise in a pool left me with a limp for about 10 days!

    It was a refreshing interview and would like to thank you for putting the truth out in the public.

    I cannot tell you the numerous people who have tried to offer “the cure” and then when it doesn’t work, I am told its because I don’t believe in the treatment!! So ostensibly, its my fault because I am not subscribing to the quackery! It actually boils down to a form of intimidation and expectation that one is entirely responsible for the unfortunate fate of having a serious and chronic malady.

    Again many thanks for your enlightening discussion.

    Yours Truly,

    Diana Warwick

  • 26 An early day motion supporting the Royal London Homeopathic Hospital « gimpy’s blog // May 24, 2008 at 12:54

    [...] shall comment little other than refer readers to this post from David Colquhoun on the efficacy of herbal medicines and his opening paragraph. A paper published in the [...]

  • 27 Dr Ann Walker removed from Register of Nutrionists // Apr 23, 2009 at 19:49

    [...] Herbal medicines fail test [...]

  • 28 Tweets that mention Herbal medicines fail test -- Topsy.com // Nov 4, 2010 at 15:25

    [...] This post was mentioned on Twitter by Ma and Ma, Dr Aust. Dr Aust said: For a sceptical view of what medical herbalists dish out: http://www.dcscience.net/?p=169 Having them in a science museum is.. hmmm…. [...]

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  • 30 ayerz // Sep 11, 2013 at 08:39

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