Although some people say homeopathy, a type of alternative medicine, is safe and leads to better outcomes when used along with conventional medicine, others say it can be harmful, and it is unethical for doctors to recommend it.

Homeopathy is based on the idea that "like cures like," meaning that diseases can be treated with substances that would produce symptoms in healthy people that are similar to the symptoms of the disease. (Such as deadly nightshade for cold and flu, or poison ivy for rashes.) 

Supporters of the practice also believe that the substances used in treatments should be diluted, because lower doses of a treatment are actually more potent. But this means that many homeopathic remedies are diluted so much that not a single molecule from the original "active" substance would remain, according to the National Institutes of Health.

As such, any ideas that homeopathic treatments could actually work to treat sick people "fly in the face of science," said Dr. Edzard Ernst, an emeritus professor at the University of Exeter in the United Kingdom, who studies complementary medicine. Controlled studies tend to show that outcomes for people who receive homeopathic treatments are indistinguishable from those of people who receive placebos, Ernst wrote in the July 14 issue of the BMJ.

Still, because there isn't any active substance present in homeopathic treatments, they are unlikely to cause serious harm, Ernst said.

In fact, Peter Fisher, director of research at the Royal London Hospital for Integrated Medicine, argues that homeopathic treatments can improve patient outcomes. Fisher, who wrote a counterpoint to Ernst's arguments, also published today in the BMJ, points to several studies that suggest that patients who use homeopathic treatments along with conventional medicine have better outcomes than those who don't. For example, one study with 450 patients who had acute upper respiratory problems, including allergies, found that after two weeks, 82 percent of homeopathic patients had no symptoms, compared with 68 percent of patients who used conventional medicine.

Other studies have found that patients who use homeopathic treatments tend to use less antibiotics and nonsteroidal, anti-inflammatory drugs, said Fisher, who also serves as editor in chief of the journal Homeopathy. [Wishful Thinking: 6 'Magic Bullet' Cures That Don't Exist]

But Ernst argued that homeopathic treatments can still be harmful if they are used in place of an effective therapy. "Nobody can say how often they have caused actual harm to patients; anecdotally, however, I know of several deaths that have occurred in this unnecessary way," Ernst said. "The ultramolecular homeopathic remedy might be harmless, but the same cannot be said for all homeopaths," he said.

The National Institutes of Health also says that there is little evidence to support homeopathy as an effective treatment, and that some products that are labeled as homeopathic can actually contain active ingredients that could cause side effects and drug interactions.

"The axioms of homeopathy are implausible, its benefits do not outweigh its risks," Ernst said. "Therefore, it seems unreasonable, even unethical, for healthcare professionals to recommend its use.

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