A Chemist’s Brief Look at Homeopathy

Joe Schwarcz, Ph.D.
December 2, 2001

I have a problem with homeopathy. To accept its principles, I must cast aside the understanding of chemistry that I have developed over 30 years. Therapy based on nonexistent molecules just does not fit the model. But, of course, I cannot conclude that homeopathy does not work just because its proposed mechanism of action is unacceptable to the current scientific view. After all, was once widely believed that due to the curvature of the earth, radio transmission across the Atlantic would never be possible because radio waves traveled in straight lines. Then it was accidentally discovered that these waves bounce off the atmosphere. However, before reconsidering our theories about molecules, we have to investigate whether homeopathy really does work.

The father of homeopathy, Samuel Hahnemann, was trained in the standard medicine of his day and began practicing in Germany in the late 1700s. He quickly became disillusioned with the treatments he had learned. Bleeding, leeches, suction cups, purges, and arsenic powders seemed to do more harm than good. Hahnemann began to ignore his training and to prescribe a regimen that at the time was quite revolutionary: fresh air, personal hygiene, exercise, and a nourishing diet. Since there was little chance of earning a living by simply recommending this regimen, he supplemented his income by using his fluency in eight languages: he undertook to translate medical texts. While working on one of these translations, he encountered an explanation of why quinine supposedly cured malaria — the substance fortifies the stomach.

Intrigued, Hahnemann took some quinine himself to see if it really had this effect. It did not, but soon he felt feverish: his pulse quickened, his extremities became cold, his head throbbed. As these symptoms were exactly like those of malaria, he reasoned that quinine cured malaria because fever cures fever. In other words, “like cures like.” Homeopathy, from the Greek homoios‘ (like) and pathos, (suffering), was born.

Hahnemann went further, and began systematically testing the effects of a large variety of natural substances on healthy people. Such “provings” led him to conclude that belladonna, for example, could be used to treat sore throats because it caused throat constriction in healthy subjects. But belladonna is a classic poison. Was homeopathy therefore dangerous? Not at all. Hahnemann had another idea. He theorized that the smaller the dose of a given substance, the more effective that substance would be in stimulating the body’s “vital force” to ward off disease. So reduced the prescribed doses by repeatedly diluting the original extracts.

The dilutions were extreme. Hahnemann was not bothered by the fact that at high dilutions, none of the original substance remained. He claimed that the power of the curative solution did not come from the presence of an active ingredient but from the fact that the original substance had, in some way, imprinted itself on the solution. In other words, the water in the diluting solution somehow “remembered” the material that had been dissolved in it several dilutions back. This imprinting process had to be carried out very carefully; a simple dilution of the solution was not enough. The vial had to be struck against a special leather pillow a fixed number of times in order to be “dynamized.”

Mainstream physicians did not take kindly to these peculiar rites. In fact, the American Medical Association was formed in 1846 largely as a reaction to homeopathy; one of its founding goals was to rid the profession of homeopaths. At times, the association’s strictures became ridiculous. One Connecticut doctor lost his membership for consulting a homeopath — who happened to be his wife.

Nevertheless, homeopathy did not disappear and its advocates gleefully point to studies in peer-reviewed scientific journals that appear to show benefit. But wait a minute. A careful review of these studies yields unimpressive results. In the treatment of a few minor conditions, homeopathy has been reported as slightly more effective than a placebo, but this has no practical implication; it merely attracts academic interest. How can there be any positive results at all when there is no active ingredient? Publication bias is one explanation. “Positive studies” are more likely than than negative studies to be reported. If enough studies are carried out, sooner or later some will have to show positive results based on the law of averages. Reporting these while maintaining silence on negative findings can create the illusion of effectiveness.

Several large reviews of homeopathic research have been published, some done by proponents and some by critics. All agree that homeopathy has not been proven clearly effective for any clinical condition. A detailed analysis of homeopathic research will be posted to HomeoWatch within the next few months.


Dr. Schwarcz is director of McGill University’s Office for Chemistry and Society. In addition to teaching chemistry at McGill, he hosts a weekly “phone-in” show about chemistry on Montreal radio station CJAD, writes a weekly column called “The Right Chemistry” in the Montreal Gazette, and has a regular TV feature entitled “Joe’s Chemistry Set” on the Canadian Discovery Channel. His books Radar, Hula Hoops and Playful Pigs and The Genie in the Bottle feature commentaries on the fascinating chemistry of everyday life.


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This article was posted on December 2, 2001.