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Complementary Medicine
Although based on lies, it can work for you if you're conscious ie. it never works if you're in a coma.

So should we stop criticising it, and accept it as effective 'placebo medicine'?

 
 
It is unscientific to pour wholesale scorn on complementary medicine

Alarmist condemnation of all alternative therapies ignores the crucial role some could play in the human healing process

Madeleine Bunting
The Guardian
Monday March 24 2008

Suckers: How Alternative Medicine Makes Fools of Us All; Snake Oil Science; and next month sees another, Trick or Treatment: what these new books have in common is varying degrees of frustration at the seemingly inexorable rise of complementary medicine. It seems the aim of some of these authors is to finish off a burgeoning health industry that they believe is based on charlatans and quacks preying on the gullible and desperate.

The books reflect the growing exasperation in some quarters that public opinion is not as amenable to persuasion and scientific evidence as they would hope. The language gets lurid; the mood music to pronouncements on complementary medicine is increasingly alarmist - we are living in dangerous times, an unEnlightenment looms as tides of irrationality threaten to overwhelm the palisades erected by science. "Reason is a precious but fragile thing," declared Richard Dawkins in his series, The Enemies of Reason, last autumn. "Reason has liberated us from superstition and given us centuries of progress. We abandon it at our peril."

What so troubles these science warriors is that it is estimated a third of people in the UK now use complementary medicine, at a cost of £1.5bn a year. In the US, the figures are substantially higher; it has been calculated that more visits are made to healing therapists than to doctors. There is an extraordinary paradox here: a half-century of astonishing conventional medical advances has not succeeded in eliminating complementary medicine. Quite the reverse: the breakthroughs in conventional medicine have been accompanied by the proliferation of other forms of healing - many of which have little or no evidence base to prove their efficacy. Indeed, it only takes a short surf on the web to discover that the wilder shores of this burgeoning industry are, well, pretty wild.

To the science warriors, this bizarre state of affairs can only be explained by irrationality. They bemoan the state of science education and lament how, contrary to expectation, literacy and access to information have failed to eradicate superstition. Meanwhile, in this increasingly sharply polarised debate, complementary medicine practitioners are equally exasperated by what they see as blinkered scientific reductionism.

So it takes a brave scientist to launch into this territory and risk getting attacked from both camps by daring to ask a simple question: is there anything science can learn from complementary medicine? That is precisely what Kathy Sykes is doing in her current television series, Alternative Therapies (the second programme is on BBC2 tonight). As Bristol University's professor of public engagement in science and the director of the Cheltenham Festival of Science, no one can challenge her credentials as a scientist, yet her scrutiny of particular therapies throws up serious challenges to conventional medicine.

Sykes is too good a scientist to give complementary medicine an easy run. Tonight she examines reflexology, and gives it pretty short shrift. There are 30,000 reflexologists working on a million British feet a year. They base their work on a theory that parts of the sole of the foot correlate to organs in the body. The only problem is that Sykes could find no one, reflexologist or scientist, who could explain how these correlations might work. Furthermore, it turned out that this "ancient" healing system seems to have originated with an imaginative American woman in the 1930s. But patients swear by it. One reflexologist points Sykes to her annual garden party full of babies and children as evidence of the success she has had with infertility problems. This is the point where most scientists snort with derision at the use of personal anecdote as evidence, but Sykes presses on and it takes her into two areas of scientific research. First, she digs up new research on the importance of touch, which can have a profound impact on the brain. Even the hand of a stranger reduces anxiety and that of someone with whom one has a close relationship is even more significant. In fact, Sykes finds some scientific underpinning which goes beyond placebo in many of the therapies she looks at. But it is placebo which emerges as a recurrent and crucially important thread in her quest, and it leads her to the work of several American scientists who are trying to identify what placebo is, who it works for, and why it works.

This is one of the most common charges made against complementary medicine - that most of it is no better than placebo. But there is a way of turning that accusation around: perhaps complementary medicine is an effective way to harness placebo as one of the most powerful - and cheapest - of healing processes. Rather than being derogatory about the phenomenon as "just" placebo, perhaps we should see it as one of the most remarkable and little understood aspects of the human body.

That line of inquiry has taken Sykes to the US several times over the course of the two series she has made. There placebo has become a new frontier in medicine. In a range of studies with startling results - even sham knee surgery can be as effective as the real thing - many factors contribute to placebo: the confidence of the doctor; the social, cultural expectations around the procedure; the empathy and warmth of the patient-doctor relationship; the patient's degree of faith. Get all these right, and the outcome can be remarkable. Harvard professor Ted Kaptchuk is publishing a study this week which shows that placebo is as good as any conventional treatment available for irritable bowel syndrome. Given that the eight most industrialised nations spend $40bn a year on medication for this condition, that's revolutionary stuff.

This kind of research into placebo gives some insight into why complementary medicine has boomed and why there are so many people who cite their own experience to passionately defend it. The average consultation with a GP is 4.6 minutes, while the complementary therapist can devote an hour to taking detailed personal histories. That time and relationship provide a context and an opportunity for the ritual and recasting of personal experience which Kaptchuk believes are the crucial elements of placebo.

Complementary medicine is most popular where conventional medicine fails, such as with musculoskeletal conditions and mental health - stress, depression, anxiety (the recent revelations about the inefficacy of Prozac were another reminder of how shaky the science is in a large area of conventional medicine). Several complementary therapies are particularly effective at pain relief - you had to see Sykes's footage of hypnotism helping a woman to have teeth extracted without anaesthetic to believe it. Kaptchuk argues that pain is not a static given but can be experienced dramatically differently.

Conventional medicine prolongs life but is less successful in prolonging good health - we can expect to spend more years of our life in poor health, as a government report showed last week - and in producing wellbeing. So people are voting with their feet, trying to find other ways to fill the gaps left by conventional medicine. We need scientists to help to identify what they are looking for and why, rather than pouring scorn indiscriminately on the whole field and on the relations between belief, mind and body, of which science still has such a fragmentary understanding.
 
Snake Oil Science
by R. Barker Bausell
 
Book review by Harriet Hall, M.D.

I could condense this review into three words: “read this book!”

The term “complementary and alternative medicine” (CAM) is relatively new, but the treatments it encompasses are not. Before we had science, all we had to rely on was testimonials and beliefs. And even today, for most people who believe CAM works, belief is enough. But at some level, the public has now recognized that science matters and people are looking for evidence to support those beliefs. Advocates claim that recent research validates CAM therapies. Does it really? Does the evidence show that any CAM therapy actually works better than placebos? R. Barker Bausell asks that question, does a compellingly thorough investigation, and comes up with a resounding “NO” for an answer.
 
Bausell is the ideal person to ask such a question. He is a research methodologist: he designs and analyzes research studies for a living. Not only that: he was intimately involved with acupuncture research for the National Center for Complementary and Alternative Medicine (NCCAM). So when he talks about what can go wrong in research and why much of the research on CAM is suspect, he is well worth listening to.

He describes his acupuncture research in great detail. It involved patients with pain from dental surgery. Before designing the experiments, he searched the literature and found an article that reviewed 16 previous trials of acupuncture for dental pain and concluded that it was probably effective. But on the Jadad scale, a simple 5-point measure of quality, none of those 16 studies scored higher than 3 (which is considered barely adequate) and 5 of them incredibly scored zero. Bausell’s group set out to resolve the question with research of much higher quality. For instance, a low dropout rate is one measure of quality; they only had 3 subjects drop out during the course of the study, and those 3 were people the researchers sent home because of a snow storm!

They compared “true” acupuncture to the most credible “sham” acupuncture they could devise. There was no difference in outcome: both were equally effective in relieving pain. When they looked more closely at their data, they found some surprises. The placebo control was not perfect, and some subjects had been able to guess which group they were in. Knowing you really got acupuncture should have increased the placebo response, and knowing you didn’t should have decreased it — yet even so, there was no difference between the groups. So the results were even more negative than they appeared. Even more fascinating, patients who thought they got real acupuncture reported much more pain relief than those who thought they got the sham, regardless of which they actually got!

Bausell points out that penicillin cures pneumonia even if you’re in a coma, but alternative medicine only seems to work when you are awake. You have to know (or think) you’re being treated. And penicillin works by well-understood scientific principles, while much of alternative medicine is based on “entire physiologic systems or physical forces that the average high school science teacher already knew didn’t exist.” If any alternative treatment clearly worked as well as penicillin, prior plausibility wouldn’t matter: science would adopt it and worry about how it worked later. Under the circumstances, prior plausibility is an important consideration.

He tells his mother-in-law’s story. She had knee pain from osteoarthritis with fluctuating symptoms. Every time the pain increased, she would try something new she had read about in Prevention magazine and every time it would seem to work as the pain naturally decreased again. And eventually it would seem to stop working as the pain naturally increased again. She would phone every couple of months to tell him about the wonderful new treatment she had discovered. She was not ignorant or stupid, but she underestimated the power of the placebo and didn’t realize how the natural fluctuations of her pain led her to false conclusions.

She had fallen for the most common human error: the post hoc ergo propter hoc fallacy. The fact that pain relief follows treatment doesn’t necessarily mean that the treatment caused the pain relief. This is only one of the many impediments to correct thinking that plague our fallible human brains. Bausell describes some of those other impediments. He shows how patients, doctors, and researchers are all equally likely to fool themselves, and why the most rigorous science is needed to keep us from reaching false conclusions.

Bausell’s thorough discussion of the placebo phenomenon is illuminating and invaluable. He covers the history of research on placebos and tells some fascinating anecdotes. He argues that placebo response is not just imagination. It is a learned phenomenon, a conditioned response. You respond to a placebo pill because you have previous experience of being helped by pills. Morphine injections in dogs cause a side effect of salivation: after a while, you can inject water and they will respond with salivation. Physiologic effects from placebo are always smaller than with the real thing, but apparently they do occur. The evidence for objective physiologic effects may not be entirely convincing, but it is certain that pain and other subjective symptoms respond to placebos. And there is even research suggesting a mechanism: the release of endogenous opioids, pain-relieving chemicals produced by our own brains. If you counteract those chemicals with a narcotic antagonist like Narcan, you can block the placebo response.

He shows that the act of taking a pill may really relieve pain, but that the contents of the pill may be irrelevant. Research shows a hierarchy of placebo response: injections work better than capsules and capsules work better than tablets. The color and size of the pill and the frequency of dosing all make a difference. And intriguingly, patients who have responded to a placebo have distortions of memory: they remember the pain relief as greater than it actually was!

Bausell points out that

…just because someone with a PhD or an MD performs a clinical trial doesn’t mean that the trial possesses any credibility whatsoever. In fact, the vast majority of these efforts are worse than worthless because they produce misleading results.

The book includes valuable lessons on how to tell credible research from the other kind. Even the most experienced researchers will find food for thought here, and for the layman it will be a revelation.

Research is full of pitfalls. Negative studies tend not to get published (the file drawer effect). Research done by believers and pharmaceutical companies tends to be more positive than research done by others. Studies from non-English speaking countries are notoriously unreliable for various reasons — 98% of the acupuncture studies from Asia are positive, compared to 30% from Canada, Australia, and New Zealand. The researcher may delegate the actual research to others, who may make undetected mistakes or deliberately skew results to please their boss. Double blind studies may not be truly blind: subjects may have been able to guess which group they were in. Subjects who are not responding may drop out. People who believe in homeopathy are more likely to volunteer for homeopathy studies. Researchers may put a positive spin on their findings or reach conclusions that are not justified by the data. Even if the research is impeccable, we arbitrarily use p=.05 as the measure of statistical significance, and this means there is a 5% probability that the results will appear falsely positive just by chance.

There are more pitfalls, and Bausell covers them all. When you come right down to it, no experiment is beyond criticism, and most published research is wrong. So how can we decide which studies are credible? We now have published guidelines such as the 22 item Consolidated Standards of Reporting Trials (CONSORT) checklist to assess the quality of randomized controlled trials, but Bausell offers some simpler criteria that can rule out the worst offenders:

Subjects are randomly assigned to a CAM therapy or a credible placebo
At least 50 subjects per group
Less than 25% dropout rate
Publication in a high-quality, prestigious, peer-reviewed journal
Using this simple 4-item checklist, he reviewed all the CAM studies published in The New England Journal of Medicine and The Journal of the American Medical Association from 2000–2007. 14 met the criteria, and all were negative. When he expanded his search to include the Annals of Internal Medicine and Archives of Internal Medicine, he ended up with 22 studies, only one of which was positive (exactly what you would expect from the 5% rule if none of them worked).

Since different studies have conflicting results, we now use meta-analyses or systematic reviews to try to reach a reliable conclusion. In fact, we even have systematic reviews of systematic reviews! After explaining why systematic reviews are subject to several pitfalls of their own, Bausell goes on to examine the high-quality systematic reviews from the Cochrane collection. Cochrane’s independent reviewers take the quality of studies into account and try to evaluate all the published evidence without bias. Of 98 CAM reviews in the Cochrane database, 21 were positive. When he subtracted those that lacked confirmation by studies in English-speaking countries, those with suspect controls, and those that were subsequently trumped by more definitive high-quality studies, the percentage of positive studies dropped to that familiar 5%.

A highly touted non-Cochrane review of homeopathy concluded that the clinical effects of homeopathy were not just due to placebo. But strangely they also concluded that there was insufficient evidence to show that any single homeopathic treatment was clearly effective in any one clinical condition. A re-analysis of the studies they had reviewed showed that when only the highest quality studies were considered, the alleged positive effect for homeopathy disappeared.

What all this amounts to is that advocates can point to plenty of “snake oil” science that apparently supports various CAM treatments; but when examined critically, the entire body of evidence is compatible with the hypothesis that no CAM method works any better than placebo. True believers will never give up their favorite treatment because of negative evidence; they will always want to try one more study in the hope that it will vindicate their belief. They see science as a method they can take advantage of to convince others that their treatment works. They don’t see it as a method of finding out whether their treatment works. Bausell says

CAM therapists simply do not value (and most, in my experience, do not understand) the scientific process.

He doesn’t aim to dissuade anyone from using CAM. He just doesn’t want anyone to choose it for the wrong reasons, to be fooled into thinking there is credible evidence where there isn’t. He emphasizes that CAM nourishes hope, and its placebos work, if only for symptoms that would eventually resolve on their own anyway. The comfort CAM brings can be valuable, as long as it is not used in place of effective treatments for serious conditions — and most of the time it isn’t, despite the occasional horror story of a patient who refuses effective cancer treatment and dies using a useless remedy. He even has some advice on how to choose a placebo therapy that works for you. He encourages you to believe because otherwise it won’t work.

Bausell writes in an entertaining, accessible style: the book reads almost like a detective story. It should appeal equally to the general reader and to the scientist. The book isn’t perfect, but its minor flaws don’t detract from its message. It is destined to be a classic on the order of Robert Park’s Voodoo Science and Michael Shermer’s Why People Believe Weird Things. If you want to understand how medical research works, if you want to know what can lead patients and scientists to false conclusions, if you have ever used complementary or alternative medicine or have wondered why others do, if you value evidence over belief, if you care about the truth, read this book.
 

When there's no real alternative

One in five of us regularly uses complementary medicine, but how much of it really works, and when does it become dangerous?

Lucy Atkins
The Guardian
Tuesday December 16 2003
Last updated at 16:25 on November 03 2005.

When Stephen Hall, 43, was diagnosed with inoperable pancreatic cancer, he did what many of us might and went to an alternative therapist who promised him that his condition was curable. Hall believed him. Last week, his "wellness practitioner", Reginald Gill, 68, from Poole, Dorset, was convicted of two offences under the Trades Descriptions Act after selling Hall an "IFAS high frequency therapy device" that would, he claimed, kill off the cancer cells. Gill had also advised Hall against chemotherapy, saying he would "go home in a box" if he did, and told him to stop taking morphine for the pain.

Instead, he put him on an extreme diet, sold him an electronic device, and charged him £75 for treatment sessions at home. The court heard that Gill told Hall after one treatment: "I've got it. I've killed the bad cells; it's just the pancreas that needs more work."

Hall died 10 weeks after the cancer was diagnosed. Last week, his mother said outside the court: "The verdict today should go a long way towards protecting the sick and the terminally ill who, in good faith, go to bogus practitioners who make false claims... Stephen was a hostage to the treatment that the so-called clinic advocated, so depriving him of any sense of normality in the last weeks of his life." Gill will be sentenced in January.

Clearly, the promises of complementary and alternative medicines (Cams) can be immensely seductive. About one in five of us use them regularly and millions swear that some therapies cure anything from stress to cancer. But when good sense is replaced by blind faith and a mistrust in conventional medicine, the use of Cams can backfire.

Last year in Melbourne, Australia, Isabella Denley, an epileptic toddler, died after her parents ditched the anti-convulsant medication she had been prescribed by her neurologist. The drugs had terrible side effects, including sleep loss and hyperactivity, so they turned to alternative therapies, visiting a vibrational kinesiologist, a cranial osteopath and a psychic who told them Isabella was suffering from a past-life trauma.

An inquest heard that when she died, the toddler was exclusively on homeopathic medication. Her parents believed they were doing their utmost. But clearly the potential pitfalls of Cams go beyond ruthless charlatans. Indeed, the real peril may be our faith that alternative therapies will inevitably reach - and cure - the parts that allopathic medicines will not.

"There is certainly evidence to show that some therapies are effective for certain conditions," says a spokesperson for the Research Council for Complementary Medicine (RCCM). But finding out which ones work for which conditions can be confusing. Often several studies of the same therapy will contradict each other, and since funding for research is hard to come by many studies are considered flawed.

The RCCM has a database with about 85,000 citations of clinical trials and research outcomes and has just received government funding to assess the quality and outcome of twelve therapies in the four NHS priority areas - cancer, coronary heart disease, mental health and chronic conditions. But so far, few Cams have been clinically proven to work. Indeed, hardly a week goes by when a study doesn't appear to disprove some Cam or other. Last week, one in the British Medical Journal showed that evening primrose oil - until recently available on the NHS to treat eczema - doesn't help the condition after all. A couple of weeks ago, the University of Washington in Seattle published findings that echinacea is no better than a placebo when it comes to treating colds in children.

Naturally, such scientific scepticism does not stop millions of us from using Cams. A recent report by Virgin money found that "spiritual spending" has soared in Britain to £670m a year (on yoga, acupuncture, massage and other such therapies). And, according to the Prince of Wales's Foundation for Integrated Health (FIH), about 20% of British people use one of eight alternative therapies (acupuncture, aromatherapy, chiropractic, homeopathy, hypnotherapy, medical herbalism, osteopathy and reflexology) between 2.8 to 5.3 times a year.

Many people use alternative remedies successfully for minor ailments and overall wellness. Others however turn to Cams in desperation after a devastating diagnosis, believing they have nothing to lose. Around 75% of breast cancer patients are estimated to have tried alternative therapies and many cancer specialists believe Cams do have an important role in pain management. Sarah Parkinson, wife of comedian Paul Merton, who died this year of breast cancer, turned in her last months to alternative therapies instead of chemotherapy, having decided that, for her, quality of life was paramount. But other cancer patients switch to alternative remedies believing they will be saved.

Doctors warn of the dangers of "pseudo-scientific" cancer remedies, such as shark's cartiledge and mistletoe, which are put forward as miracle cancer cures. These, they say, are causing some patients who may benefit from conventional medicine to ditch it entirely, sometimes with dire consequences. One study this year in the European Journal of Cancer found that the death rate for cancer patients who were also users of alternative medicine was greater than for non-users. While no conclusions were reached about why this was, some doctors believe it is a misplaced faith that may lead us to eschew conventional treatments, such as chemotherapy, that could save our lives.

So, do we put too much faith in alternative therapies? Many of us, when we get some new symptom, now turn to a trusted alternative therapist without first seeing our GP. Of course, most reputable therapists will immediately refer you to a doctor if your symptoms seem worrying. But what if they don't? Misdiagnosis - or failure entirely to diagnose a serious condition - can have devastating consequences. James Turner, an 11-year-old Canadian boy, was taken to a chiropractor by his parents when he developed chest pains while swimming in July 2000. The chiropractor twice adjusted his neck and back without taking x-rays. Soon after, James was rushed to a children's hospital, having lost control of his legs and bowels. He was given an MRI and neurosurgery for a benign tumour (a ganglioglioma) on his spinal cord.

This type of tumour is non-cancerous and slow-growing - with proper detection and medical treatment about 75% of afflicted children escape paralysis if the spinal cord is undamaged at the time of diagnosis. James's tumour, however, had been damaged (the parents, who are suing the chiropractor, say this was caused by the chiropractor's manipulation). James is now a paraplegic.

Nobody is saying that chiropractic per se is dangerous (indeed, many studies show it can be very beneficial for certain conditions). Chiropractors, and therapists from other established disciplines such as osteopathy or homeopathy state openly that they are not (necessarily) trained physicians. But still we assume they will spot any danger signs. Dr Stephen Zeitzew, chief of orthopaedic surgery at the West Los Angeles Veterans Administration Healthcare Centre, speaks for many doctors when he says this is a tall order: "Often diagnosis and treatment is challenging even to physicians with particular expertise. It is clearly true that on occasion the lack of diagnosis [by Cam practitioners] puts our patients in danger".

Such concerns echo a seminal House of Lords report in 2000 which warned: "One of the main dangers of Cam is that patients could miss out on conventional medical diagnosis and treatment because they choose only to consult a Cam practitioner". Zeitzew also points out that if your chosen practitioner is less than above board, the risks accelerate.

One alternative "helpline" was recently singled out by Which? magazine for giving misleading advice on prostate problems after a doctor phoned, posing as a concerned member of the public and describing symptoms of prostate cancer. The doctor was offered an expensive herbal supplement and told that his symptoms were not necessarily anything to worry about.

Of the eight most popular therapies in Britain, only two (chiropractic and osteopathy) are regulated by law in the same way dentists, doctors and nurses are. Acupuncture and herbal practitioners could be about to follow suit. "Things are changing," says Simon Mills, research coordinator of the University of Exeter's complementary health program. "Practitioners are recognising their responsibility to the public, to patients, and to themselves."

But most currently rely on self-regulation by organisational bodies to ensure high standards, safety and accountability. "Choose an alternative therapist who belongs to a reputable professional body," advises Mills. If you go to a herbalist it is particularly important that the herbs come from reputable sources (The National Institute of Medical Herbalists or the Register of Traditional Chinese Medicine provide fully trained practitioners).

Michael MacIntyre, chairman of the European Herbal Practitioners Association (www.euroherb.com) says: "You should always ask whether they belong to a credible organisation with a code of practice and disciplinary procedure, and whether they have insurance."

The Foundation for Integrated Health is also about to publish guidelines on how to choose a practitioner, and anyone considering alternative therapy would be wise to consult them. The bottom line is clear: the vast majority of alternative therapists are well trained and reputable.

Cams themselves are rarely dangerous. But the way we use them just might be.

So do they work?

Herbal medicine

Use of plant extracts to treat wide variety of disorders and maintain good health - physically and mentally. About 30% of the population spends about £31m a year on herbal remedies.

Does it work? Professor Edzard Ernst, Britain's only professor of complementary medicine, wrote in the British Medical Journal this October: "The evidence on herbal medicines is incomplete, complex, and confusing". A recent overview of herbal medicine included 23 systematic reviews of rigorous trials of herbal medicines. Eleven came to a positive conclusion, nine yielded promising but not convincing results, and three were negative.

Dangers: Between 1968 and 1997, the World Health Organization's monitoring centre collected 8,985 reports of adverse incidents associated with herbal medicines from 55 countries. Ernst points out that this number amounts to only a tiny fraction of adverse events associated with conventional drugs held in the same database.

Risks: Unreliable sources, adulteration of Chinese herbal treatments with synthetic drugs, misbranding, lack of standardisation, possible side effects (one study found that some herbs, such as St John's wort, gingko biloba and echinacea in high doses could reduce fertility). Also a possible danger of reactions with prescription drugs.

Some banned herbs: Aristolochi: for "nephrotoxicity" (kidney damage). Kava: for causing "heptatoxicity" (liver damage). Ephedra: banned in the US by the International Olympic Committee, the National Football League, the National Collegiate Athletic Association, minor league baseball, and the US armed forces following some deaths from over use.

Chiropractic

Treats musculo-skeletal complaints by adjusting muscles, tendons and joints using manipulation and massage techniques. (as does osteopathy, said to have similar benefits to chiropractic.)

Does it work? The 2000 House of Lords report states that there is "good evidence of the efficacy of osteopathy and chiropractic. Indeed, they appear to be somewhat more effective than the manipulative techniques employed by conventional physiotherapists"

Dangers: Misdiagnosis or failure to diagnose specific conditions. See a GP for a diagnosis and/or referral.

Homeopathy

Treats a wide range of physical and mental complaints using minute dilutions of animal, vegetable and mineral substances that in higher doses could be harmful. This is said to stimulate the body to heal itself. According to the WHO, homeopathy is the second most commonly used form of health care in the world after herbal medicine.

Does it work? Huge, ongoing scientific debate. Homeopathic solutions are diluted so many times that many scientists argue they are unlikely to contain any of the original ingredients at all. But in 2001 a study found that dissolved molecules do not simply spread out in a regular fashion in the solution but tend to clump together in bigger clusters of molecules - and then as even bigger lumps composed of these clusters. This could explain how a heavily diluted homeopathic remedy might contain more of the "active" ingredient than expected.

Individual remedies produce varied scientific results: one hay-fever trial found a noticeable improvement in patients taking a homeopathic remedy over those in the control group. Another recent trial found that arnica does nothing to reduce pain or accelerate healing after surgery.

Dangers: Misdiagnosis/failure to diagnose serious conditions.

Acupuncture

The House of Lords report said: "There is also scientific evidence of the efficacy of acupuncture, notably for pain relief and the treatment of nausea".