Early in the 19th century European hospitals were the place where one went to die. In an age of no medical knowledge about pathogens, bacteria and infections as disease perpetrators, physicians and nurses rarely washed their hands in between patients.

Bloodletting was a common practice for "preventing" and "curing" diseases and toxins were often prescribed as medicine, so those who could afford medical care in many cases only hastened their death and shortened their suffering. Those were the days in which Samuel Hahnemann laid the foundations for what is known as homeopathy. Hahnemann did not believe in the then prevalent medical practices such as bloodletting, whose purpose was to purge the blood of "bad humors". Instead, he believed that proper medicine should focus on stimulating what he called the "vital force" or "spirit-like medicinal powers" inherent to the body in a manner that would restore the harmony of these powers, the loss of which is the real cause for disease. Thus, it is not surprising that at the time Hahnemann's medicinal approach gained much popularity and based itself as an alternative to traditional medicine. In fact, Hahnemann need not have done much for the improved well-being of at least some of his patients in comparison to traditionally-cared-for patients. It was sufficient to avoid poisoning them or infecting them with more severe disease. In the two centuries that have passed since then, conventional medicine has undergone many changes in light of our understanding of pathogens and how they can be dealt with. In contrast, followers of the homeopathic approach have clung to the basic principles laid out by Hahnemann, despite contradictory scientific discoveries.

At the heart of homeopathy are several basic beliefs, most of which can be traced to Hahnemann's methods and writings. The main principle states that "like cures like", and this is the idea behind the "proving" system for testing which remedies can cure specific diseases (proving originated from prüfung, the German word for "test"). Hahnemann believed that in order to cure certain symptoms the homeopathic healer should employ the same substances that cause these very symptoms. For this reason, the proving process could only be performed on healthy individuals rather than on people inflicted with a disease and already symptomatic. From those days until now any homeopathic remedy is tested by giving it to healthy individuals and recording the symptoms over weeks and months. Thus, homeopathic treatment begins with evaluation of the symptoms presented by the patient and finding a substance that causes these symptoms in healthy individuals. This substance will be used as remedy for the patient.

But of course things are not so simple. The second principle of homeopathic medicine makes sure that the substance will not reach the patient… In fact, a homeopathic remedy contains no active ingredients, but only water and the inactive ingredients that make up the formulation of the solid tablet. Hahnemann believed that for the treatment to be effective the patient should be given a solution that contains a minimal amount of the symptom-causing substance. Hence he suggested that the end solution should be obtained by serially diluting a concentrated solution to a level of 1 in 1060 the original concentration.

At the time there was no good understanding of the chemical and physical properties of atoms and molecules as we understand them today. Amedeo Avogadro has yet phrased the Avogadro limit, which states that when a material undergoes a dilution greater than 1 in 1024, the end solution may not contain even a single molecule of the material. The higher the dilution, the less likely it is for a tablet to contain any trace of the material. In fact it is no longer a solution, since there are no solutes, only the solvent (water). As world-renowned scientific skeptic James Randi put it: "this would be tantamount to grinding a grain of rice into tiny particles, dissolving it in a sphere of water the size of our Solar System, and then repeating this process about 2 billion times." One of the ways by which followers of homeopathy deal with such criticism is their claim that water retains a memory of the substance: even after it is gone its properties are embedded in the water molecules.

Moreover, according to the homeopathic approach, the higher the dilution of the substance the more effective the remedy is. This in contrast to conventional medicine and toxicology, in which dose-response curves show that the higher the concentration (dosage) of a drug, the more potent is its effect, at least to a certain degree. The inverse correlation claimed by followers of homeopathy cannot be backed up by any rule of physics or chemistry.

Chemically, a homeopathic remedy cannot be distinguished from plain water.

There are several direct problems that arise from the guiding principles of homeopathy. Testing the substances on healthy individuals and extrapolating the observations to determine their potential to cure diseases is unheard of when it comes to any proven drugs that do not cause any of the symptoms they are supposed to cure. In fact, homeopathy is marked by an absurd situation in which certain substances supposedly serve to cure conditions in a manner that is completely opposite to their known effect. Take for example caffeine, on which homeopathic sleeping pills are based. While it is possible that a substance, when taken at a low dose, may have a reductive effect on one of the symptoms it causes, this is far from being a universally accepted principle. Another soft spot in the theory of homeopathy is the notion that diluting the substance to a level that it is completely absent from the solution somehow preserves the properties of that substance, and that further dilutions only enhance the effectiveness of the remedy. The idea that water can "remember" and pass the information on to adjacent water molecules is highly problematic. Any water molecule within the homeopathic solution has come into contact with an infinite number of other water molecules, all of which have come into contact with still other water molecules along the years. According to this rationale one can suggest that all water on the face of the Earth "remembers" any material with which it ever came into contact. Hence, it cannot be explained how the water in a homeopathic solution remembers only the "curative" substance added by the homeopathic pharmacist, but not other substances it met along the years.

Homeopathy as an alternative medical approach has been around for two hundred years, but only the last few decades have seen scientific attempts to assess its effectiveness, using similar methodology to that applied in conventional medicine. The aim of one of the largest studies was to collect data from dozens of studies on the effect homeopathic remedies on sick individuals. The scientists wanted to examine whether the effect of such remedies can be distinguished from the placebo effect, which is a psychosomatic benefit that has been attributed to fake (placebo) drugs. At first this study did indeed find that the homeopathic effect is superior to the placebo effect, but following a more thorough examination of the data it was realized that most studies in the field are of poor scientific standards and are not properly controlled, and that the studies characterized by higher scientific standards showed less and less positive results. Such poor quality studies can be easily biased and their results are considered dubious. Another group of researchers took this task one step further and compared each homeopathic study to similar studies in conventional medicine. In this case more trustable studies were employed. Here, no significant difference between homeopathy and the placebo effect was found, while conventional drugs did show a significantly superior benefit compared to placebo. The conclusion of this study was that there is no evidence of homeopathy having any real medical value.

Experiments in recent years added skepticism to the medical value of homeopathic remedies.

There are some alternative explanations for the benefits of homeopathy supposedly experienced by some patients, aside from the placebo effect. In most severe chronic diseases there are natural oscillations in the severity of the symptoms, and people tend to turn to alternative medicine during the peak of the disease. In such cases their improvement cannot be attributed to the homeopathic treatment, but to natural processes that take place in the body. It is only the temporal proximity between their visit to the homeopathic healer to the improvement in their symptoms that lead these people to mistakenly connect between the two. Another explanation is that homeopathic healers often recommend patients to change their life style alongside the homeopathic treatment. Exercise and a healthy diet can most certainly improve the physical and mental well being of anyone, an improvement that has nothing to do with the treatment.

The danger that lies in homeopathy does not arise from the treatment itself, which, at least scientifically, is no different from drinking water and taking a placebo drug. The danger is that people who are receiving homeopathic treatment may not turn to proper medical advice. Such people may not receive the actual medical treatment that they require over a long period of time since they are under the false belief that homeopathy is a proven and appropriate alternative. Although there are some homeopathic studies that showed positive results, in depth evaluation of these studies has shown that they were not properly conducted. The more scientifically appropriate studies that have demonstrated the ineffectiveness of homeopathy should be taken as a clear warning sign against relying on homeopathy as an acceptable medical approach.

Ido Kaminsky
Department of Biological Chemistry
Weizmann Institute of Science
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