Homeopathy: an alternative approach to healing, or the prototypical pseudoscience, depending on who you ask. It’s been around for over two centuries, and still has many devotees across the world. But by all empirical standards, homeopathy is simply not scientifically sound. Let’s unpack what homeopathy is, what people believe about it, and why we can be so sure it’s not real science.

Where did homeopathy come from?

Some people may use the term “homeopathy” as a kind of catch-all for different types of alternative or complementary medicine. But it’s very important that we specify what we’re talking about, as different branches of alternative medicine comprise different sets of beliefs and techniques. Homeopathy is a form of alternative medicine, but not all alternative medicine is homeopathy.

Homeopathy has its roots in Europe. It was founded by German physician Samuel Hahnemann, who published his first essay on the subject in 1796, followed by a comprehensive book in 1810.

Hahnemann began to practice his innovation whilst living in Leipzig, but hostility from local apothecaries forced him to move to the city of Köthen in 1821. Not everyone was opposed to the new system of homeopathy, however. In 1835, Hahnemann relocated to Paris where his methods were welcomed, and where he remained until his death – reportedly as a millionaire – in 1843.  

By this time, Hahnemann’s ideas had spread far and wide. The American Institute of Homeopathy was established in 1844, and training colleges and academies began springing up all over the place. What is now the Royal London Hospital for Integrated Medicine was founded as the London Homeopathic Hospital in 1849, one of a handful of sites across the UK where homeopathy was practiced according to Hahnemann’s principles.

Acceptance of homeopathy nowadays varies greatly between different cultures and communities. The actual King of England is a fan, along with numerous other famous faces. 

However, general feeling among the medical establishment in the global north is that we should move away from homeopathy, with government funding for it being withdrawn in countries like the UK and France, and the Australian health authorities ruling that it is ineffective and “should not be used to treat health conditions that are chronic, serious, or could become serious.”

It’s never been quite as popular in the US as in Europe. A 2012 survey found that 2.1 percent of US adults had used homeopathy within the preceding year – a 2016 analysis of the data described its use as “uncommon” but concluded that people who do use these remedies are more likely to use other complementary therapies too.

In Hahnemann’s native Germany, homeopathic remedies are widely available and used. Ear, nose, and throat specialist Dr Christian Lübbers told Undark that he was concerned many people in the country aren’t fully aware of what homeopathy is and how it differs from other alternative medicines. In early 2024, Health Minister Karl Lauterbach reportedly issued a recommendation that government health insurance funding for homeopathy should finally be scrapped, pointing out, "We also cannot fight climate change with dowsing rods."

By contrast, as a 2024 review explains, many Asian and African nations do not consider homeopathy to fall under the definition of “quackery”, and are much more accepting of its inclusion in healthcare. Traditional health practices in several of these countries incorporate homeopathic principles, such as traditional Iranian medicine and the Indian AYUSH system (Ayurveda, Yoga, Naturopathy, Unani, Siddha, Homeopathy). 

As we dive deeper into what homeopathy is, we’re looking very specifically at the ideas developed by Hahnemann, and not at other systems of alternative or complementary medicine. 

Homeopathy’s popularity has waxed and waned over the years, but it never quite went away, even as medicine and science were advancing through the many great breakthroughs that defined the 20th century.

What beliefs underpin homeopathy?

A key principle of homeopathy, as established by Hahnemann, is that a symptom can be relieved by administering a substance that would cause the same symptom in an otherwise healthy person. 

This idea of the importance of similarity was not new, and Hahnemann was inspired by many physicians and thinkers from the ancient world through the Middle Ages – perhaps most notably, the Renaissance philosopher and physician Paracelsus, the "father of toxicology" who coined the phrase "the dose makes the poison". 

Hahnemann also made most of his conclusions about what substances would treat what symptoms based on testing them on healthy people. Say, for instance, you give some leaves you’ve found to Bill the farmer, and five minutes later his nose is bleeding like a faucet; according to Hahnemann, those leaves must therefore be the perfect remedy for Betty the cheesemaker, who has been plagued with nosebleeds all summer. Of course, we don’t need to actually test the remedy on Betty – we just know.

Perhaps not the most serious example, but it does illustrate the premise that Hahnemann was working under. 

So far, so comparatively simple. Whatever we may think about these premises nowadays, you can kind of see how Hahnemann reached his conclusions based on the observations and understanding that were available to him. But this is where things get a bit weird.

In its other major guiding principle, homeopathy moves out of the realms of science altogether and firmly into the esoteric. See, there was something missing from the Ballad of Bill and Betty. Once you’ve established that your leaves are the cure Betty needs, you don’t simply give them to her. First, you need to dilute them hundreds of times, forcefully shaking the mixture in between (succussion), in a ritualistic process called potentiation, or sometimes potentization.

Those who subscribe to homeopathy believe that the active substance contains a “spiritual healing power” that is transferred into the very molecules of the solvent you’re using to dilute it – often plain old water. The idea is that the more dilutions you do, the more powerful your concoction becomes. 

Have a look next time you’re in your local drugstore – you might find a homeopathic remedy or two on the shelves, and they’ll be labeled with a number and a letter. A common one is 30C: 30 refers to the number of dilutions that were performed, and C – the Roman numeral for 100 – means that each dilution was 1:100 and that the mixture was shaken 100 times.

In a 30C tincture, the original substance has been diluted in a ratio of 1:10⁶⁰. That is really, really, diluted.

Unfortunately, that doesn't really wash when we require things like evidence to show medicines actually have some effect before giving them out to people.

How do homeopathic beliefs go against scientific knowledge?

It’s important to consider homeopathy, at least during the early days, in the context of what was known about conventional medicine at the time. Mainstream medical practices back then were equally unscientific by today’s standards, and in some cases actively harmful. Homeopathy would probably have seemed a gentler, much more appealing alternative.

However, in the intervening years, modern medicine has moved on a lot. Procedures and treatments in use today have to meet rigorous standards of testing, and humanity’s understanding of the underlying workings of the human body, how disease occurs, and how pharmaceutical products function, has progressed beyond a level that 18th-century physicians could even dream of. 

So, as convincing as Hahnemann’s ideas clearly were to his acolytes, even decades and now centuries after his death, there’s just one problem: there’s absolutely no concrete scientific evidence to support them.

The similarity principle is flawed by its very nature, based on prescientific ideas that were understandable at the time – walnuts look a bit like the brain, so maybe they can be used to have some effect on the brain – but now seem fairly ridiculous. That means the whole house of cards on which homeopathy is built has very shaky foundations.

We’ve also alluded to the fact that the standard of “evidence” that most homeopathic remedies are based on is far below what is required for conventional drugs. 

Clinical trials take a long time, and only happen once several rounds of preclinical testing – usually in lab tests and then in an animal model – have demonstrated that a potential new drug is worth pursuing further. Lots of compounds never make it through this rigorous process. The ones that do get approved only make it to market once there is strong evidence to show that they’re safe and effective. 

Even if any homeopathic remedies do have pharmaceutical activity – which is very unlikely, but we’re getting to that – none of them have yet met this standard. No homeopathic remedy has been approved by the US Food & Drug Administration, for instance. 

But leaving all of this aside, the dilutions that homeopathic remedies go through – which, remember, is part of what makes homeopathy, homeopathy – mean that essentially no active ingredient remains in any of these products. The whole idea that successive dilutions increase the “potency” of a solution is contrary to everything we understand about the physical world. There’s just no getting away from the fact that if you dilute a substance by a factor of 10⁶⁰ in water, you’re basically left with plain water.

And homeopathy advocates don’t try to obfuscate this reality. They don’t deny that essentially no active ingredients remain in dilutions of this magnitude. It’s just that in a world where water has memory and serial succussions can transfer spiritual energy, leaving no physical trace of your ingredient behind simply does not matter. 

The take-home

By any scientific measure, homeopathic “remedies” do not – cannot – work. They contain no active ingredients and are produced using methods built on premises that fall apart when held to the same standards of evidence as any conventional medicine. 

As one 2020 paper put it, "It is evident that – from the very beginning – Hahnemann and his acolytes were immune to scientific evidence, which questioned their dogmatic system."

We should stress once again here that we are only talking about homeopathy as it is practiced according to Hahnemann’s teachings. This should not be taken as a comment on any other branch of natural, complementary, or alternative medicine or therapy. There are plenty of “natural” or herbal products on the market that are not homeopathic.

The only plausible mechanism by which true homeopathy can have any sort of impact on the body is the placebo effect, which is real and powerful, but cannot replace conventional medicine. 

If you have a serious bacterial infection, for instance, you’re going to need antibiotics. If, as well as those antibiotics, you would like to take a homeopathic pill that you feel helps you, that’s unlikely to be harmful. But where people may be encouraged to eschew lifesaving medicines in favor of a solely homeopathic approach? That’s where we’ve got problems. 

Complementary therapies can provide great comfort and relief to people as an adjunct to conventional medicine. Promoting a patient’s well-being, as well as their physical healing, should ideally be part of any treatment plan. But there’s a gaping chasm between, say, enjoying a soothing herbal tea blend, and diluting that tea by a factor of one novemdecillion to somehow make it “stronger”. 

Ultimately, it benefits no one to perpetuate the myth that the belief system underpinning homeopathy is anything other than pseudoscientific.