Probing Question: Does homeopathy work?

old kit with many brown bottlesMichelle Enemark

Tiny 19th century homeopathy kit at the Semmelweis Medical Museum, Budapest, Hungary

Mahatama Ghandi used it. So did Mark Twain and John D. Rockefeller. Cindy Crawford, Paul McCartney, Oprah Winfrey and Prince Charles are all said to be fans. The object of their admiration? Homeopathy, a non-toxic method of treating illnesses characterized as pure genius by its fans and pure quackery by its opponents.

The formulation of homeopathic remedies starts with the creation of a concentrated tincture, made by crushing specific herbs, minerals, or animal substances and then diluting them in either alcohol or lactose solution. Homeopaths then further dilute this "mother tincture" as needed when treating patients, according to this medical system's philosophy that the more dilute a substance is, the greater its strength.

This thinking runs counter to the way dose-response relationships work in conventional drugs, namely that substances have no effect at the smallest doses but can be toxic or even fatal in large amounts. Some homeopathic remedies are so dilute that it is mathematically almost impossible that even one molecule of the original substance remains in the remedy. Proponents believe that vital energetic properties of the substance nevertheless remain.

The controversy surrounding the homeopathic philosophy hasn't hurt sales. The American Homeopathic Pharmaceutical Association estimated that in 1995 U.S. retail sales of homeopathic medicines amounted to more than $200 million, with growth of at least 20 percent per year. The number of homeopathic practitioners in the United States grew from fewer than 200 in the 1970s to approximately 3,000 in 1996.

But does homeopathy work?

"I don't know if it works," says Kelly Karpa, associate professor of pharmacology in the Penn State College of Medicine, " The whole basis of homeopathy is counterintuitive to everything pharmacologists have learned about drug actions. I won't say that I buy into it 100 percent, but I won't say that I think it's quackery either. Having never used it myself, I try to keep an open mind. Some patients are convinced that it has helped them. Perhaps the greatest parallel between homeopathy and conventional medicine is the practice of immunization, which also relies on the principle that small amounts of a substance may protect from disease."

Samuel Hahnemann, a German physician and chemist, developed homeopathy in the late 1700s, when he discovered that a South American medicinal plant called cinchona—sometimes used in that era to treat malaria—caused symptoms of that same disease when taken by healthy people. This led Hahnemann to test many other substances and develop a medical principal he called The Law of Similars.

"The principal behind the law of similars, is that like cures like," explains Karpa. So if a substance causes a disease in large amounts, then it was theorized that the same substance in really small amounts could heal or protect from the disease." For example, if your cold symptoms include a runny nose and watery eyes, your homeopathic remedy might include a very dilute amount of Allium Cepa, better known as an onion. If you have an itchy skin rash, it's likely that a homeopathic dose of Rhus toxicodendron—poison ivy—would be the advised remedy.

These dilutions represent one advantage of homeopathy—they leave very little risk of harm from the remedies themselves. The main risk of homeopathy may come from patients foregoing conventional treatments that are proven to help, says Karpa, adding that people may choose homeopathic remedies if they've become disillusioned with conventional medicine. "Maybe they've been harmed by a drug or had a bad experience with a conventional practitioner," she says, "so they're looking for something that they perceive as more natural. Many homeopathic products are based on diluted plant parts."

Karpa also believes that homeopathy can give people—especially sufferers of chronic diseases such as fibromyalgia, chronic fatigue syndrome, and irritable bowel syndrome, for whom conventional medicine may not be much of a help—a sense of empowerment in that they're doing something to help themselves.

The problem, says Karpa, is that very little science—in the form of double-blind, placebo-controlled randomized clinical studies— has been done to test whether homeopathy actually works. Where such tests have been done, Karpa says, homeopathic remedies often perform little better than placebos. While there may be a bias against homeopathy in the conventional medical literature, she adds, "From that perspective, the burden of proof remains on the homeopathic community."

Homeopathy has found greater acceptance with the medical establishments in Europe, India and Latin America than it has in the United States, and is routinely used as a low-cost and nontoxic alternative to conventional medicine in some countries. For instance, in England, homeopathy has long been a part of the health care system (the Royal Family has its own homeopathic physician) and is a recognized postgraduate medical specialty; in France, pharmacies are required to stock homeopathic remedies alongside conventional (allopathic) medicines.

So should you throw away your homeopathic tinctures and pills? Maybe not, says Karpa. "My thinking is that if people who are using them think they're getting a benefit and it's not causing them any harm, then why stop it?"

Kelly J. Karpa, Ph.D., R.Ph., is associate professor of pharmacology in the Penn State College of Medicine,

Last Updated February 02, 2009