Homeopathy is one of the biggest alternative-medicine industries, and as a result of its infamy it has been heavily studied. The conclusions of these studies is that homeopathy itself does not work1,2,3,4 and only poorly controlled experiments are more likely to show that it works5. It is founded on confused and nonsensical ideas that have been proven to be false, and products can have unexpected side-effects6. Homeopathic solutions are prepared through a series of dilutions that are so pronounced (30C) that not a single molecule of any active ingredient is found in the resultant water - the full dilution rate for a standard preparation of 30 dilutions of 1 drop in 100 is one in 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,0007,4. The theory is that the water has "memory", that diluting the chemical makes the cure stronger, and that this memory is somehow what cures disease. The original solution is sometimes based on a "like cures like" principal, whereby a chemical that causes similar symptoms is used, and other potions are based on the same type of basic thinking as found in herbalism. It works only by psychological side-effects8, and is akin to confidence-trickery, and as such Homeopathy works best on illnesses that have a strong psychological component, and on illnesses that come and go naturally no matter what interventions you make, like the common cold. Dr Ben Goldacre notes that "Homeopaths [... talk] about 'aggravations', explaining that sometimes the correct remedy can make symptoms get worse before they get better, and claiming that this is part of the treatment process. [...] Literally anything that happens to you after a treatment is proof of the therapist's clinical acumen and prescribing skill"9. Because people do not understand concepts such as statistical regression (most illnesses get worse then get better, all on their own) nor the placebo effect (the power of positive thinking on the body), many people are tricked into thinking that homeopathy works.1,2,5. Also, as most people don't understand what homeopathy is, many products are sold simply without the customer realizing that they're not buying medicine and that the products have not been tested to the same standards as medical products8.
“In the USA up to 4 in ten adults use 'some form' of alternative therapy10. In Britain there are about 150 000 alternative therapists, and the public spend about £4.5 billion on them (as of year 2009)11. In nearly all practices, they work due to the psychology surrounding 'treatment' (the placebo effect and statistical regression) rather than the actual result of the treatment. This is why drugs companies spend more on branding and advertising than they do on research and development12. Nearly all alternative therapies are psychological trickery rather than real medicine13. All such practices are called quackery by skeptics. The danger is that many people seek help from 'alternative' providers before they seek proper medical help, which can result in delayed treatment and in the worst cases, death from ailments that are otherwise perfectly curable if only the sufferer had gone to a normal doctor sooner10. "Some homeopathic remedies may contain substances that are not safe, or that interfere with the action of other medicines" and a real doctor should be consulted before using alternative therapies14 (including those that say they are 'natural' - so are many poisons).”
“Just beginning a career in medicine in 1781, Samuel Hahnemann, an idealistic young German physician, quickly became disillusioned with the medicine of his day [for example] the treatment of malaria with cinchona bark, or quinine. Curious, he experimented with it on himself, and experienced symptoms similar to those of malaria. It was a turning point in his life. On the basis of this single personal anecdote, he declared the Law of Similars: "Like cures like," or similia, similabus, curantor. A substance that causes certain symptoms in a healthy person, he concluded, could be used to treat illnesses that have the same symptoms. [...]
[He] began experimenting with all kinds of natural substances, attempting to match up the symptoms they induced in healthy people with the symptoms of various illnesses. Unfortunately, some of the side effects associated with the use of these substances were serious [so] in an effort to reduce the severity of the side effects, he took the rather obvious step of diluting the medicine. As you would expect, dilution reduced the side effects, but to his astonishment Hahnemann also observed that patients given the dilute medication recovered more quickly from their illness. At that point, you and I might have concluded that the medicine was preventing them from getting better. [...]
Hahnemann attributes healing to a spiritual "medicinal energy," which he says is most powerful "when it communicates nothing material." He wrote, for example, that smallpox and measles can be transmitted from one child to another without anything material being passed, comparing it to the force a magnet exerts on a needle it does not touch. This is "vitalism," the belief that life involves some spiritual essence beyond chemistry or physics. It was the prevailing medical superstition of the time. [...]
Fortunately for Hahnemann´s patients, the Law of Infinitesimals cancelled the Law of Similars. Your baby has diaper rash? Dr. Hahnemann´s prescription, based on the Law of Similars, would be to treat baby with something that causes a rash. He prescribed the herb Rhus toxicodendrum, more commonly known as poison ivy. Fortunately for baby, the Law of Infinitesimals calls for a 30C dilution of rhus toxicodendrum, more than enough to ensure that not a single molecule of the toxin could remain in the medication. If the affected area is kept clean and dry for a few days, the diaper rash will disappear - and homeopathy will be credited with another success. [...]
Hahnemann´s Organon of the medical Art even specified exactly how many times the solution was to be shaken between subsequent dilutions (four). Homeopathy today is still practiced straight out of Hahnemann´s two-hundred-year-old Organon.”
Medicine has come on a long, long way since the 18th century.
“Since it was written, the assumptions on which homeopathy is based have been totally refuted. [...] Scientific discoveries in Europe and Britain were about to alter the landscape. [...] The germ theory of disease, emerging from the work of Pasteur and Koch after the death of Darwin, would prove to be the death of such superstitious nonsense as vitalism and such appalling treatments as bleeding and purgatives. [... Now, ] Avogadro´s number has been measured to five significant figures, and most diseases have been found to be caused by germs. And yet Hahnemann´s procedures for preparation of homeopathic medications are still rigorously adhered to by his many thousands of followers. Meanwhile, science has shown homeopathy to be nothing more than a quaint superstition.”
After a national review of medical practices stemming from the Flexner Report in 1910, homeopathy's flagship institution, the Samuel Hahnemann Hospital, stopped practicing homeopathy8.
“Homeopaths who are not medically qualified can miss fatal diagnoses, or actively disregard them, telling their patients grandly to stop using their inhalers, and to throw away their heart pills. There are plenty of examples, but I have too much style to document them here.”
“There is no legal regulation of homeopathic practitioners in the UK. This means that anyone can practise as a homeopath, even if they have no qualifications or experience. [...] Some homeopathic remedies may contain substances that are not safe, or that interfere with the action of other medicines. You should talk to your GP before stopping any treatment prescribed by a doctor or avoiding procedures such as vaccination in favour of homeopathy.”
Homeopathy has continued to operate in not only a non-scientific manner, but often in an anti-scientific one - "it's routine marketing practice for homeopaths to denigrate mainstream medicine" notes one researcher6. In the West life is relatively peaceful, diseases are under control, and populations are mostly vaccinated. The worst that homepathy can do is occasionally manifest side-effects and impair real medicine, very occasionally cause death, and increase ignorance of real cause-and-effect in certain communities. But elsewhere, homeopathy has much worse effects.
In Botswana one-quarter of the population is HIV positive. They need organized medical aid, and good instruction, and proven solutions. But homeopath fund-raising campaigns have seen homeopathic products sold en masse to the people there, combined with vitriolic and paranoid-sounding attacks on mainstream medicine.6
Homeopaths have been consistently and erroneously advising - telling - patients not to accept vaccinations such as the MMR - "one study found that more than half of all the homeopaths approached advised patients against the MMR vaccine for their children"6.
Homeopaths oppose even well-established medical treatments in favour of their own "alternative" and "holistic" solutions. "A BBC Newsnight investigation found that almost all the homeopaths approached recommended ineffective homeopathic pills to protect against malaria, and advised against medical malaria prophylactics"6
In some countries such as the USA and the UK, homeopathy is powerful enough to allow mass confusion to spread about what has been medically tested, and what is homeopathic. For example in 2004-2005 the USA suffered a severe shortage of the flu vaccine due to a supply chain failure. "the Wall Street Journal ran a long article on flu shot alternatives [but included] oscillococcinum, a homeopathic medication, as an option. The only mild caveat was that "the homeopathic mechanism is questionable""6. Needless to say, despite what oscillococcinum packaging says, the drug has no effect at all on the flu virus nor its symptoms. Official medical advice is that certain people should routinely seek a medical solution for the flu (such as the elderly). But those who purchase oscillococcinum could easily and mistakenly think that they need nothing else, in which they are being put at risk (and as oscillococcinum is a $15 million-dollar business (annually) in the USA and even more in Europe8, many people fall for its claims.
The very statement that "water has memory" should be enough to put most educated people off of homeopathy straight away and it is one of the most widely ridiculed aspects of homeopathy. This is because water does not have memory, and it requires some pretty "special" thinking to even think that this is a possibility - let alone a possibility that happens to result in water's memories being able to cure Human diseases. How does the water know what to remember? Water molecules are so small and get mixed around so much, that a glass of water has collectively been through millions of toxins, poisons, sewers, countless other living bodies, and has been excreted in urine and faeces far more times than it has ever been near drugs that, when digested in the correct way, might help alleviate symptoms of a particular illness. The practitioner of homeopathy never mentions all of that! Even one of the great defenders, Benveniste, fails to explain this facet2. In addition, as a result of its simplicity, ubiquity and usefulness, the water molecule has been studied a lot by scientists. There is not a shred of evidence anywhere that water has memory. To put it in the same mild manner as Dr Goldacre, who has studied homeopathy, the very idea that water could have "memory" has "large conceptual holes"5.
The other absurdity, which clearly hasn't been thought out in much detail beyond "that's an interesting idea" is that if you dilute something, it makes it stronger. It can be easy to forget what a daft idea this is when reading homeopathic literature, and a good solution (no pun intended) is to instead talk about a well-known drug and see how the homeopathic theory sounds in that case, also remembering the idea that if a drug causes symptoms in a healthy person, it will have the opposite (curing) effect in an ill person:
“If coffee keeps you awake, according to homeopathy dilute coffee will put you to sleep. The more dilute, the stronger the effect. If you keep diluting it until there isn´t a single molecule of coffee left, it will be even stronger. The water will somehow remember the coffee. If you drip that water onto a sugar pill and let the water evaporate, the water´s memory will somehow be transferred to the sugar pill, and that memory of coffee will somehow enable it to function as a sleeping pill.”
Dr Harriet Hall (2014)4
Repeated peer-reviewed scientific studies into homeopathy have found that it has no effect beyond the indirect placebo effect (which occurs when any treatment is given due to the client's positive perception). I emphasized peer-reviewed articles because there are many poor "scientific" studies that have concluded that homeopathic water is effective, but reviews of all tests that take into account the quality of the test have revealed that "there is an almost linear relationship between the methodological quality of a homeopathy trial and the result it gives. The worse the study - which is to say, the less it is a 'fair test' - the more likely it is to find that homeopathy is better than placebo" (Dr Goldacre 2008)5. "There are single studies that have found statistically significant differences between control groups and groups treated with [Homeopathy], but none of these have been replicated or they have been marred by methodological faults. An evaluation of five reviews of homeopathic studies has been done by Terence Hines who found that more than one hundred studies have failed to come to any definitive positive conclusions about homeopathic potions. There have been at least twelve scientific reviews of homeopathy published since the mid-1980s. Guess what? Homeopathic remedies are not more effective than placebos or no intervention1"2. A landmark meta-analysis of all studies into Homeopathy was published in the most prestigious medical journal, Lancet, in 2005, taking into account a huge number of trials3. This "was only the latest in a long string of meta-analyses to show that homeopathy performs no better than placebo"5.
“To simply advise consumers that homeopathy is used to treat many health problems or that craniosacral therapy may prevent migraine attacks (Pinder et al. 2005) may look like a tempting shortcut to some, but it is hardly good enough evidence. Without evidence, we have no means of knowing whether such advice is helpful, irrelevant, or perhaps even detrimental. [...] An emphasis on prevention and self-care based on wishful thinking distracts from the few evidence-based preventative strategies currently available and is therefore counterproductive.”
Dr Edzard Ernst (2007)
“David Colquhoun, a professor of pharmacology at University College London, says that ignoring evidence (large-scale studies have shown homeopathy, for example, to be no more effective than a placebo) is ridiculous. "What can the idea of proper training in homeopathy actually mean?" he asks.”
So what do homeopaths themselves make of the evidence? Obviously, because their product relies on psychological self-trickery, nearly all homeopathic commentary is based around testimonials ("It worked for me!", "These happy customers can't all be wrong!), and therefore places it amongst the crazy fads of history that are an embarrassment to humankind's heritage. Some other arguments are also used:
“Homeopaths sometimes argue that because homeopathy is individualized, it can´t be tested in randomized controlled trials or judged by the same standards as conventional medicines. They are wrong: it can. Homeopaths could individualize their prescriptions as usual, the remedies could be randomized and coded by a second party, and they could be dispensed by a blinded third party who didn´t know whether what he was handing out was what the homeopath ordered or a substitute. Homeopaths involved in designing homeopathy studies have conspicuously chosen not to design them this way. [...]
Homeopaths love to cite statistics from nineteenth-century cholera and typhoid epidemics where patients treated with homeopathy were more likely to survive than patients treated with conventional medicine. Those historical successes are easily explained. [...] In 1800, conventional medicine was a disaster. Doctors weakened patients with bloodletting and purging, they poisoned them with mercury and other harmful substances, and they often killed more patients than they cured. [...] Doctors of the time were using remedies that often actively caused harm, but homeopathic remedies did nothing so of course the results were better. Homeopathy was just a way of avoiding iatrogenic harm.”
Dr Harriet Hall (2014)4
It is highly recommended that you seek out the Skeptical Inquirer article by Dr Hall, and read the other sources I've been using as references on this page, for a wealth of information on some of the evidences for/against homeopathy.
The UK government executed one of the biggest investigations, involving proponents and opponents, and the resultant House of Commons report (2010 Feb 22) was completely clear that not only was the evidence completely against homeopathy14, but that so much research had already been done that there was no point in anyone doing any further studies - all questions have already been answered. Some bullet points from the document and Dr Ernst's reporting of it:
'The systematic reviews and meta-analyses conclusively demonstrate that homeopathic products perform no better than placebos'.
'We regret that advocates of homeopathy, including in their submissions to our inquiry, choose to rely on, and promulgate, selective approaches to the treatment of the evidence base as this risks confusing or misleading the public, the media and policy makers'.
'The committee expressed considerable doubt about the validity of the 'like cures like' principle, one of the fundamental assumptions of homeopathy. [...] The second assumption of homeopathy, that diluting remedies renders them not weaker but stronger, was considered 'scientifically implausible' by the committee. The Members of Parliament (MPs) added: 'Even if water could retain a memory of previously dissolved substances, we know of no explanation for why the sugar-based homeopathic pills routinely dispensed would retain such a memory'.
The committee considered the frequently voiced notion that more research into homeopathy is required in order to resolve open questions. The MPs strongly opposed this view: 'There is enough testing of homeopathy and plenty of evidence showing that it is not efficacious... we cannot see how further research [...] is justified. [...] It is also unethical to enter patients into trials to answer questions that have been settled already'.
'[Patients] require an explanation that homeopathy is a placebo. When this is not done, choice is meaningless. When it is done, the effectiveness of the placebo - that is, homeopathy - may be diminished. We argue that the provision of homeopathy on the NHS, in effect, diminishes, not increases, informed patient choice'.
Some UK institutions had taken to supporting homeopathy and to studying its traditions. But the scientific reaction has been steadily increasing in outrage and effectiveness, and the UK's National Health Service reports on homeopathy thusly:
“The National Institute of Health and Care Excellence (NICE) advises the NHS on proper use of treatments. NICE currently does not recommend that homeopathy should be used in the treatment of any health condition.”
"David Colquhoun, a pharmacology professor at University College London, has shamed some universities into ending alternative courses. The number of homeopathic hospitals in Britain is dwindling"17. There is a chance that with continued pressure, such rubbish can be kept far at bay from any institution, and its practitioners can be pressurized into ceasing to make the pseudoscientific medical and health claims that they are too often caught making.
The_placebo_effect is a positive effect on an illness or medical condition, or on a health-related outcome, that results from suggestion and expectation18. This subtle psychological effect occurs whether or not the underlying treatment actually works and it is strong enough to continually distort medical studies into the effectiveness of health products and can make products seems effective when they are not - it can even do the same for surgical practices.19,20. Such unexpected effects have been studied in greater and greater detail by medical researchers, and it has emerged that placebo effects come in various forms21. The placebo effect is particularly significant in areas such as pain relief and stress, and is therefore best at overcoming aches and pains, headaches, stress-related conditions including recovery from stomach ulcers18 and skin rashes. Most complementary and alternative medicines (CAM) and alternative therapies work through indirect psychological effects, and by the turn of 20th century many New Age related remedies and practices were based on cures by suggestion22. The placebo effect is the reason why these remedies appear to work for so many people, when in reality they don't have any medical effect20,23,24,25,26,27,28,29 and its effects can often support erroneous ideas as to how disease works, and how healing works.
How does it work? (1) There is a link between mood and mental states of mind, and between mood and our immune system, meaning, that our overall impressions of a treatment can affect our outlook, which can boost our immune system30,31,32. (2) When it comes to pain, the prefrontal cortex of the brain can suppress pain messages from the insula33 and other places, meaning that if we prime ourselves to feel less pain (such as when expecting a pill to work) then it really does dull pain. Many experiments have confirmed the ability of people to mentally control pain. (3) Classical conditioning means that many elements of merely receiving a treatment cause our brain to release neurotransmitters and other learned responses in anticipation of feeling better, which improves how we feel19,34. (4) The Hawthorne Effect - people tend to live healthier and perform better simply because they are being studied24,34. (5) Receiving treatment can boost confidence and reduce stress, both of which can improve healing and feelings of wellbeing19,34,35. Finally, (6) It works best when delivered by a confident doctor who also believes the placebo will work36.
For more, see:
“People... probably do not even notice the word "homeopathic" printed in small letters on the box. Many would have no idea what it means if they did. Most people believe any medicine sold in America must have been proven to be safe and effective. Unfortunately, that´s not the case. [...] Congress has seen fit to enact certain exemptions to... food and drug laws. In particular, Senator Royal Copeland of New York, who was a homeopathic physician before entering the Senate, was the chief sponsor of the 1938 Food, Drug and Cosmetics Act. It included a provision explicitly exempting all homeopathic medications listed in the Homeopathic Pharmacopoeia from FDA oversight. That exemption is still on the books today. Copeland's justification for the exemption was quite simple: there is no way to confirm that a homeopathic preparation is what it claims to be. The effect of the exemption was to give homeopathy an edge over all the other snake oil on the market.”