Does Homeopathy Work? The evidence for homeopathy’s effectiveness includes three areas of research: 1) general comparisons of homeopathic remedies and placebos; 2) studies of homeopathy’s effectiveness for particular clinical conditions; and 3) studies looking for biological effects from potencies, especially ultra-high dilutions. Data for general effectiveness include systematic reviews and meta-analyses of randomized, placebo-controlled trials. Some investigators believe that it is reasonable to combine trials of different populations, interventions, and outcome measures when the question is whether comparison groups (homeopathic and placebo) are generally different (27), but others are skeptical of such approaches. Data for the effectiveness of homeopathy for specific clinical conditions require homogeneous sets of studies with similar populations, diagnoses, and outcomes. Data on the biological effects of high dilutions are investigated with laboratory studies under carefully controlled conditions (5). We orient the reader to these three types of evidence. Is the Homeopathic Remedy More Effective than Placebo? Four comprehensive, independent systematic reviews or meta-analyses have examined the question of whether homeopathic therapies behave like placebo in randomized, placebo-controlled trials These have comprehensively searched for all clinical trials and have used standard methods for quality evaluation and analysis of clinical trials. These reviews have found that, overall, the quality of clinical research in homeopathy is low. When only high-quality studies have been selected for analysis (such as those with adequate randomization, blinding, sample size, and other methodologic criteria that limit bias), a surprising number show positive results. For example, Kleijnen and colleagues (28) did a detailed quality evaluation of 60 homeopathic clinical trials and concluded that they "would be ready to accept that homeopathy can be efficacious, if only the mechanism of action were more plausible." Linde and colleagues (29) reviewed 119 placebo-controlled trials of homeopathy and evaluated them with an established quality scale for clinical research (the Jadad scale [34]) and a rigorous internal validity scale that examined detailed trial characteristics known to bias results. Multiple subset and sensitivity analyses on many quality variables reduced but did not eliminate an effect in favor of homeopathy. One could eventually eliminate the effect in favor of homeopathy by applying combinations of unusually selective criteria (such as picking a few of the very best studies and simultaneously adjusting their results for both small sample size and presumed publication bias), thereby decreasing the number of studies included (30, 31). There are other reviews of the clinical homeopathic literature, but these have not been comprehensive, did not use acceptable systematic review methods, or focused on a subtype of homeopathic practice (32, 33, 35) Unfortunately, even the best systematic reviews cannot disentangle components of bias that may exist in small trials, nor can they rule out that true effects may be obscured with pooling of heterogeneous studies (36, 37), thereby making it impossible to draw definitive conclusions. Is Homeopathy Effective for Particular Conditions? Patients and most clinicians want to know whether a treatment works for a particular condition, not whether homeopathy is more effective than placebo in general. Several series of randomized, placebo-controlled trials have been done on single conditions with homeopathy and have been reviewed by using good-quality criteria. These studies provide evidence that classical homeopathy does not prevent migraine (38) and that the homeopathic remedy Arnica montana does not alleviate delayed-onset muscle soreness after exercise (39). The quality reviews on the effects of Arnica montana for postoperative recovery are mixed (40, 41). Some evidence shows that the homeopathic preparation Oscillococcinum is effective for the treatment of influenza but not for its prevention (42) and that the remedy Galphimia glauca is efficacious for the treatment of allergic rhinitis (43). In several other conditions, most notably postoperative ileus (44), asthma (45), and arthritis (46), the evidence from controlled trials is inconclusive; independent replications have not been attempted or the results of trials are mixed. Recently, Taylor and colleagues (47) published the fourth in a series of high-quality, double-blind, placebo-controlled trials of homeopathic immunotherapy. In these trials, patients with allergic rhinitis or asthma were given homeopathic (serially agitated) dilutions of their primary allergen or a placebo after a 2-week placebo run-in phase. Visual analogue scales used to measure symptomatic change have consistently shown greater improvement in the homeopathically treated groups (47). A larger study using a similar protocol did not reproduce this clinical effect, although it reported immunologic findings with homeopathic immunotherapy that were different from those seen with placebo (48). In a series of three high-quality double-blind, placebo-controlled studies on childhood diarrhea, Jacobs and colleagues (49, 50) reported that classical homeopathy reduced the duration of loose stools by about 0.7 day. Double-blind randomized, placebo-controlled trials on a few other conditions have also been published. Do Ultra-High Dilutions Produce Effects in the Laboratory? Clinical trials are less sensitive for determining whether ultra-high dilutions have specific effects than laboratory research, where more rigorously controlled conditions are possible. The publication of laboratory investigations of ultra-high dilutions has produced considerable controversy and mixed results on attempted replication (52-54). Still, unusual effects of ultra-high dilutions in rigorous laboratory studies continue to be reported (55-59). Multiple independent replications of this research have not yet been done because there are few investigators in the field (60). Future research should focus on simple clinical or laboratory models that can be easily attempted by multiple investigators. In addition, better data are needed to examine the use and effects of homeopathy by the public and in actual practice (5, 29, 61). Conclusions Homeopathy is an alternative therapeutic system based on the "Principle of Similars" and the use of "minimum" doses. Homeopathy was a prominent component of 19th-century health care and recently has undergone a revival in the United States and around the world. Despite skepticism about the plausibility of homeopathy, some randomized, placebo-controlled trials and laboratory research report unexpected effects of homeopathic medicines. However, the evidence on the effectiveness of homeopathy for specific clinical conditions is scant, is of uneven quality, and is generally poorer quality than research done in allopathic medicine (61). More and better research is needed, unobstructed by belief or disbelief in the system (62). Until homeopathy is better understood, it is important that physicians be open-minded about homeopathy’s possible value and maintain communication with patients who use it. As in all of medicine, physicians must know how to prevent patients from abandoning effective therapy for serious diseases and when to permit safe therapies even if only for their nonspecific value. Annals of Internal Medicine 4 March 2003 | Volume 138 Issue 5 | Pages 393-399 Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.