Overview of Homeopathic Research

Stephen Barrett, M.D.

Homeopathy contends that substances that produce symptoms in healthy people can cure symptoms in sick people, that diluting and shaking substances makes them more powerful, and that "remedies" that contain no molecules of the original "active ingredient" can exert powerful therapeutic effects. None of these ideas makes sense.

Advocates also assert that research backs their claims. But a close look shows that this is not true. To prove that a treatment works, it is necessary to demonstrate that it is more effective than doing nothing. This requires showing that similar patients getting the treatment do better than patients who do not. The vast majority of homeopathic substances have never been tested in this way. Nor have combination OTC or dietary supplement products that contain one or more homeopathic ingredients.

A few "positive" homeopathy studies have been published in major medical journals. Proponents trumpet these studies as proof that "homeopathy works." Even if their results could be consistently reproduced (which seems unlikely), the most that studying a single remedy for a single disease could prove is that the remedy is effective against that disease. It would not validate homeopathy's basic theories or prove that homeopathic treatment is useful for other diseases.

Most reports of homeopathic research appear in publications that have little or no scientific recognition and are not readily accessible. However, several review teams have taken the trouble to gather what they could and have published detailed analyses of what they found. The most comprehensive review was conducted by the Australian Government's National Health and Research Council (NHMRC). In 2013, the NHMRC published a 301-page overview report that evaluated 57 previous reviews and the studies they had considered. The report concluded:

The quality and comprehensiveness of the systematic reviews included in this Overview Report were limited by the inclusion of many poorly designed, conducted and reported primary studies. Importantly, most of the primary studies were small in size and likely to be insufficiently powered to detect a statistically significant outcome. Also, this Overview Report was reliant upon the reporting within the included systematic reviews, which was not always high quality. In addition, several systematic reviews did not provide specific conclusions relating to each clinical condition included in the review. . . .

There is a paucity of good-quality studies of sufficient size that examine the effectiveness of homeopathy as a treatment for any clinical condition in humans. The available evidence is not compelling and fails to demonstrate that homeopathy is an effective treatment for any of the reported clinical conditions [1].

In 2015, the NHMRC summarized its views in a 40-page information paper that concluded:

The Bottom Line

The overall state of homeopathic research is easy to describe: Most is worthless, and no homeopathic product has been proven effective for any therapeutic purpose. In 1999, The Medical Letter on Drugs and Therapeutics, which is the medical profession's most trusted drug advisory newsletter, summed up what health professionals should be should be telling patients:

The chemical content of homeopathic products is often undefined, and some are so diluted that they are unlikely to contain any of the original material. These products have not been proven effective for any clinical condition. There is no good reason to use them.

I agree. There is also no good reason to waste scarce research dollars on further tests.


  1. Evidence on the effectiveness of homeopathy for treating health conditions. NHMRC Information paper, March 2015.
  2. Overview Report: Effectiveness of Homeopathy for Clinical Conditions: Evaluation of the Evidence. Prepared for the NHMRC Homeopathy Working Committee. Optum, October 2013.
  3. Homeopathic products. The Medical Letter 41:20-21, 1999.

This article was revised on August 1, 2015.

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