LETTER A Critical Overview of Homeopathy Flávio Dantas, MD, PhD; Peter Fisher, FRCP; and Hagen Rampes, MBChB, MRCPsych TO THE EDITOR: Homeopathy has become increasingly popular with consumers throughout the world. It is also highly controversial. In this context, we welcome Jonas and colleagues’ critical overview (1). Such an overview is not an easy task because of the different operator-dependent techniques used in homeopathic practice. We wish to point out some shortcomings in this overview. A comprehensive review of homeopathy should consider adverse effects. A systematic review done by 2 of us (2) showed that the mean incidence of adverse effects was greater with homeopathic medicines than with placebo in 11 controlled clinical trials (relative risk, 1.8) but that the effects were minor, transient, and similar in type in both study groups. A single trial of influenza prophylaxis heavily biased the results. If this trial were excluded, the relative risk would be 1.3 (Table). The main risks associated with homeopathy seem to be indirect, relating to the prescriber rather than the medicine. To our knowledge, no studies have adequately investigated this, and government regulation of homeopathic practitioners varies widely among different countries and legislatures. Homeopathic pathogenetic trials or "provings" are said to be the basis of the knowledge of homeopathic medicines, but Jonas and colleagues do not mention that many of these volunteer studies were done in the recent past. A systematic review by 2 of us (3) concluded that there is a strong negative correlation between quality and the number of pathogenetic effects (that is, low-quality studies yielded more symptoms). In other words, more subtle symptoms, mainly psychological, could be false and thus could bias criteria for homeopathic prescriptions. Finally, we highlight the question of sample size. Trials of homeopathy and other forms of complementary medicine are frequently relatively small and statistically underpowered. Unfortunately, perhaps because most scientists view homeopathy as having low "prior probability," they often interpret "absence of evidence" as "evidence of absence" of effect. For instance, in a recent study of the effect of homeopathic arnica, postoperative patients receiving placebo required 45% more analgesia than those receiving 1 of 2 homeopathic treatments (4). The study was interpreted as negative. The investigators did not report 95% confidence intervals, which is regrettable since the study was clearly underpowered to detect what was certainly a clinically relevant difference. The answer, of course, is larger, better-quality trials. But these also need larger budgets! References: 1. Jonas WB, Kaptchuk TJ, Linde K. A critical overview of homeopathy. [PMID: 12614092] Ann Intern Med. 2003;138:393-9. 2. Dantas F, Rampes H. Do homeopathic medicines provoke adverse effects? A systematic review. British Homeopathic Journal. 2000;89(Suppl 1):35-8. 3. Dantas F, Fisher P. A systematic review of homeopathic pathogenetic trials (‘provings’) published in the United Kingdom from 1945 to 1995. In: Ernst EA, Hann EG, eds. Homeopathy: A Critical Appraisal. London: Butterworth-Heinemann; 1998:69-97. 4. Stevinson C, Devaraj VS, Fountain-Barber A, Hawkins S, Ernst E. Homeopathic arnica for prevention of pain and bruising: randomized placebo-controlled trial in hand surgery. [PMID: 12562974] J R Soc Med. 2003;96:60-5. Annals of Internal Medicine 21 October 2003 | Volume 139 Issue 8 | Page W-73 Author and Article Information From Federal University of Uberlândia of São Paulo; São Paulo-SP, 04039-020, Brazil; Royal London Homeopathic Hospital; London W1W 5BP, United Kingdom; and West London Mental Health NHS Trust; Middlesex UB1 3EU, United Kingdom 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.