Homeopathy is one of the most popular and fastest growing alternative “medicines.” People are drawn to its alluring claims of “treating the whole person” and “having no side effects” like moths to a flame. Nevertheless, I generally find that most people who believe in and use homeopathy don’t actually understand how it supposedly works, and many of them are shocked when they learn its actual claims. In fact, homeopathy is based on such utterly ludicrous premises that you don’t even need complex science to debunk it. Its claims are so outlandish that it basically debunks itself. If, for example, you tell me that an herb cures a particular illness, then in the absence of scientific testing, I will grant you that the claim is plausible, because some herbs do actually have medicinal value. To know for sure whether or not it works, we would, of course, have to actually scientifically test the herb in a controlled experiment. In stark contrast, homeopathy doesn’t even need to be tested because it’s supposed mechanisms are extremely implausible and conflict with some of the most basic and well established scientific laws and concepts. Therefore, it is my intention to simply explain the fundamental claims of homeopathy and apply some basic common sense and everyday examples to illustrate how truly insane they are.

Premise 1: Like cures like

Homeopathy is based on three fundamental premises (all of which were derived well before modern science), and if any one of these premises is flawed, then homeopathy fails. The first premise is that “like cures like” (also known as the “Law of Similars” which, to be clear, is not a “law” in the scientific use of the word). The idea is that if you are sick, then you should take something which would give a healthy person your symptoms. If that sounded insane, that’s because it is. Remember, homeopathy predates modern science and the germ theory of disease. So it was invented before we realized that bacteria, virus, etc. make us sick, and before we understood how the immune system works. So it’s hardly surprising that its fundamental claims seem absurd today now that we know how diseases actually work. What is surprising, however, is that people still write massive checks to buy this stuff.

Just in case the idea of like curing like didn’t seem silly to you, let me give an example. Suppose that you have insomnia and are having trouble sleeping. Caffeine would give a healthy person your symptoms. Therefore, according to the concept that like cures like, caffeine should cure your insomnia. Think about that for a second: caffeine (a drug that we know keeps you awake) is supposed to make you sleep. That just doesn’t make sense.

To give one more example, if you are having allergy problems resulting in sneezing and your eyes watering profusely, homeopaths often recommend “Allium Cepa” (a.k.a. onion extract). You see, onions make healthy people sneeze and cry, therefore (according to the twisted “logic” of homeopathy), onions should make people who are already sneezing and crying stop sneezing and crying. Makes perfect sense right? (note the sarcasm)

Premise 2: Diluting something makes it stronger

The second premise has to do with serial dilutions. To make a homeopathic remedy, you take your active ingredient (see premise 1), then put it through a series of dilutions, and, supposedly, the more diluted that it is, the stronger that it is (this is also known as the “Law of Infinitesimals”, again the term “Law” is being used inappropriately here). So, for example, if you were going to use the Allium Cepa treatment that I mentioned earlier, you wouldn’t simply use an onion, rather you would repeatedly dilute it. So you would take a volume of the chemical extract and dilute it in nine times that amount of water, resulting in a 1 in 10 dilution. In other words, if you had 1 milliliter (ml) of chemical, you would add it to 9 ml of water. Next, you would take 1 ml of that solution and add it to 9 ml of water. Then you would take 1 ml of that solution and add it to 9 ml of water. You would do this over and over again. Typical homeopathic treatments usually involve about 20-30 dilutions, but some use 60 or more, and, importantly, the more diluted they are, the more powerful they are (according to homeopaths anyway). Note: some homeopathic dilutions use 1 in 100 rather than 1 in 10, which makes them even more dilute.

Common sense and everyday experience tells us that this is utter non-sense. At some point in time, all of us have probably bought a concentrated cleaning solution and the bottle told us to dilute it to avoid damaging the surface that we were cleaning. Why did it give us that instruction? Because diluting something weakens it! This is just common sense: if you add more water, it will become less powerful. It doesn’t take a genius to figure that one out.

To further illustrate this, I want to use an example that I have previously used: homeopathic beer. If this premise was actually true, if diluting something actually made it more potent, then you should be able to make beer far more potent simply by diluting it in water. So, give it a try the next time that you are having a party. Take one cup of beer and mix it with nine cups of water, then take one cup of that and mix it with nine more cups of water. Set a bowl of that out at your party and see what happens. If this premise is true, then people should get drunk from that much more easily than from regular beer, but I think we all know what would actually happen: the people drinking the diluted “homeopathic beer” would remain sober (note: last time that I used this example, some people were critical because I didn’t account for the other premises, but that response completely misses my point: if it was true that diluting something makes it stronger, then [regardless of the other premises] my “homeopathic beer” would be more potent then regular beer, but it’s clearly less potent, therefore that premise must be wrong).

Finally, realize that most actual homeopathic treatments are so dilute that there is literally no active ingredient in them. Homeopathy was invented before we understood that chemicals are made of molecules which are made of atoms. In other words, it was invented before we understood that chemicals could not be divided an infinite number of times. Now that we understand that, we have this fun thing called Avogadro’s number which every freshman chemistry student learns about. It tells us how much of a giving chemical is in a solution, and when we crunch the numbers for homeopathic solutions, we find that anything that has been diluted more than about 12 times usually won’t contain one single atom of the original chemical. Further, remember that many solutions are diluted 30 or even 60 times! They are quite literally just water. Chemically, that is what they are: water.

Premise 3: Water has memory

Unsurprisingly, homeopaths have a response to the criticism that their medicines are just water. Namely, they claim that water has memory. According to them, during the dilution process, the essential essence or healing properties of the chemical get memorized or retained by the water. When making a homeopathic remedy, you’re supposed to tap the solution against something between each dilution and that is supposed to magically make the chemical’s properties enter the water. It also helps if you click your heels together three times and say, “there’s no place like Quackville” (sarcasm). Once again, modern science (and common sense) tells us that this isn’t how things work. For one thing, we know how and why chemicals work, and it has to do largely with the exchange of electrons. There is no magical “healing property” that can be extracted from a chemical, rather, it is the chemical itself which reacts. Further, there is utterly no evidence that water has memory, and every day life tells us that it doesn’t. Think about it for a second, all water on the planet is constantly recycled. So, the water that you drink has been through various rivers, streams, swamps, underground reservoirs, etc., it has been pooped and peed in countless times (in fact, at one point it probably was pee), it has had dead fish decay in it, it has been exposed to countless chemicals that are toxic in high doses, etc. So why doesn’t water remember all of those things? As one of my friends likes to say, “if water had memory, then it would mostly have the properties of s***.”

Just in case you aren’t convinced, let me ask you this: do you or anyone you know own a fish tank? Do you/they use a filter? If water actually has memory, then filters are totally pointless because filters remove chemicals and particulates, but if water has memory, then the water itself (which passes through the filter) should remember the properties of the chemicals and particulates. If homeopathy works, then filters cannot possibly work and vice versa. However, we all know that filters work, which means we all know that water doesn’t have memory, which means we all know that homeopathy doesn’t work. It’s that simple.

Finally, the hypocrisy of homeopaths is on full display if you read their recommendations for making remedies, because many of them recommend using distilled water (some recommend ethanol instead, but the same basic criticisms apply). Distilled water is simply water that has been evaporated off, then condensed from the steam in order to purify it and remove chemical contaminants. Like filters, it works quite well, but it shouldn’t work if water has memory! Think about it, if water can remember the properties of chemicals after the chemicals themselves have been removed, then what good is distilling or filtering it? According to homeopathy’s own premises, distilled water should be no different from regular water.

Claim: Homeopathy has no side effects

This is not a premise of homeopathy, but it is one of their most common claims, and it’s actually true, but here is the catch, it’s true because homeopathy is just water! As I have previously explained, anytime that something claims to have no side effects, you can be assured that it is a load of crap. It’s just not plausible that something is going to have effects without also having side effects. Chemicals simply aren’t specific enough to only do what you want them to in something as complex as your body.

Conclusion: It’s just water!

Let me put this in a way that everyone can understand: if you had two identical bottles, one of which contained distilled water and the other of which contained a typical homeopathic remedy (i.e., made using over 12 dilutions), there is not one single chemist anywhere in the world who could tell you which one was which because they would both be pure water! All three of homeopathy’s fundamental premises are obviously flawed to the point of being absurd, and there is just no science to back them up. Nevertheless, millions of people swear by it. As a result, at this point I usually get one of two claims. First, people will say, “but I’ve used homeopathy (or know someone who has) and it worked!” The problem is of course that this is an anecdote. It’s meaningless. In fact, it’s a post hoc ergo propter hoc fallacy to claim that the homeopathic remedy cured you. There are countless other variables that you didn’t account for. For example, it could have simply been a placebo affect, or perhaps your body just healed itself shortly after you took the remedy, thus giving the appearance that the remedy worked. You simply cannot rule out those possibilities, only careful scientific testing can do that, which brings me to the second response: citing studies on homeopathy.

It is true that there are a number of studies that claim to support homeopathy, but it is important to remember that not all scientific publications are of a high quality (see my recent post on how to assess scientific research). The vast majority of those studies suffer from poor methodology and extremely small sample sizes. Further, even the ones that appear to have been done properly are invalidated by the fact that they aren’t repeatable (suggesting that they were statistical flukes). If a scientific result is actually correct, then other scientists should be able to replicate the results, but that just isn’t the case with homeopathy. In other words, if homeopathy actually worked, then you should consistently get the result that it is better than a placebo, but the reality is that numerous studies have confirmed that it is just a placebo. Here are a bunch of literature reviews and meta-analyses, all of which lead to the same conclusion: it’s just water (Ernst and Pittler 1998; Ernst 2002; Shang et al. 2005; Ernst 2010; NHMRC 2013 [this last one is perhaps the most thorough one to date]).