Medical science is once again pounding on alternative medicine–that is, treatments and cures that science cannot or has not validated. But the fact remains that many people who chew on tree bark and quaff bitter-tasting concoctions swear that they work, and industries that are virtually unregulated happily supply the remedies and the lore and testimonials about how the latest potions are miracle cures for everything from cancer to acne.

Some of these treatments date back centuries to when shamans and healers discovered plants that seemed to alleviate disease. For instance, in old Europe, to relieve pain and reduce fever, physicians including Hippocrates gave patients a bitter powder ground down from the bark of willow trees–a substance that led to the development of aspirin.

Homeopathy is not so ancient. Launched in the late 17th century by the German physician Samuel Hahnmann, homeopathic medicine contends that the natural chemicals that cause symptoms in healthy people will, when given to patients in minute amounts, cause those symptoms to go away. Hahnmann surmised that the tiny amounts triggered the body’s defenses to fend off the symptoms. Homeopathy is also associated with a holistic approach to treating people: practitioners spending time comforting and talking to patients and tending to their spiritual life as part of the healing.

Homeopathy remains popular in Europe and is taught in many medical schools. Yet only a few universities actually award Bachelor of Science (BS) degrees in homeopathy, including six universities in the United Kingdom.

Modern science, however, has found no evidence that homeopathy works. In a commentary in this week’s Nature, pharmacologist David Calquhoun of the University College in London derides the BS degree programs in the United Kingdom for teaching “anti-science.” A report in the same issue compares the teaching of homeopathy to students pursuing a BS degree in the United Kingdom with attempts to teach creationism as scientific fact in U.S. schools. The suggestion is that both are in the realm of pseudoscience.

Yet legions of patients are convinced that homeopathy and other alternative medicines work, leading scientists to surmise that these remedies have a placebo effect.

This comes as many drugs developed by scientists in drug companies fail in human trials because the active ingredient that researchers so painstakingly identified and tested turns out to work no better than a placebo. Drugs derived from natural products have a particularly high placebo effect–meaning that when patients think they might be getting a drug derived from a plant, they want it to work so badly that in many cases it does.

In a 2000 article about the placebo effect published in the New York Times Magazine, the writer Margaret Talbot offered,

“The truth is that the placebo effect is huge – anywhere between 35 and 75 percent of patients benefit from taking a dummy pill in studies of new drugs – so huge, in fact, that it should probably be put to conscious use in clinical practice, even if we do not entirely understand how it works. For centuries, Western medicine consisted of almost nothing but the placebo effect. The patient who got better after a bleeding – or a dose of fox lung, wood lice, tartar emetic or any of the other charming staples of the 19th-century pharmacopoeia – got better either in spite of them or because of their symbolic value. Such patients believed in the cure and in the authority of the bewigged gentlemen administering it, and the belief gave them hope and the hope helped make them well.”

Rather than deriding such practices as homeopathic medicine as quackery, modern science should endeavor to better understand why they seem to work–or at least why so many people believe that their health improves when they consume, say, a potion containing tiny amounts of aloe to treat their hemorrhoids. A growing body of science also suggests that patients get better more quickly when physicians and other healers treat them more holistically–a problem for medical doctors in the United States today who are forced by insurers to spend only a few minutes on each patient.

People getting well after erroneously believing that they have had surgery or after taking a sugar pill–this is powerful medicine, but why? Learning the answer seems like an interesting project for science, and it might shed some light on why those shamans dancing around fires–not to mention the degree candidates in British universities learning about extracts of lavender–might know something that today’s scientists do not.

Report: Giles, Jim, “Degrees in homeopathy slated as unscientific” Nature 446, 352-353 (22 March 2007) | doi:10.1038/446352a;

Commentary: Colquhoun, David, “Science degrees without the science”, Nature 446, 373-374 (22 March 2007) | doi:10.1038/446373a;