Conventional scientists confirm that clinical trials show homeopathy has beneficial effects beyond placebo, but dismiss the result as ‘noise’.

A recent study by Sigurdson et al.1 selected 50 randomised placebo-controlled trials (RCTs) of homeopathy and calculated the overall size of the treatment effect detected. They found that 80% of the trials were positive for homeopathy, and that homeopathy was twice as likely to have a beneficial effect than placebo (mean effect size 0.36, Odds Ratio 1.94). This positive result is consistent with the findings of an earlier rigorous study which found that individualised homeopathic treatment was 1.5- to 2-times more likely to be beneficial than placebo2.

And yet, Sigurdson et al. dismissed these positive results as simply being the result of ‘noise’ or ‘bias’, claiming that they demonstrate the level of error found in all clinical trials rather than demonstrating a real clinical effect of homeopathy.

To arrive at this position the authors made two key assumptions:

  1. Homeopathy is a “null field”, i.e., “a scientific field where there is nothing to discover and where observed associations are thus expected to simply reflect the magnitude of bias”3.
  2. All placebo controlled RCTs of homeopathy essentially test placebo against placebo, i.e., there is no possibility that beneficial effects seen are genuine or attributable to treatment.

Such flawed logic by experienced conventional scientists requires further comment.

‘Bias’ refers to various sources of error that may distort the results of a study, caused by weaknesses in the study design, analysis or reporting. Bias is known to impact treatment effects detected in RCTs. Researchers are aware of this and take measures to minimise bias when planning and performing studies. Homeopathy researchers are no different in this regard, carrying out clinical trials using the same trial designs and following the same quality guidelines as those used in conventional medical research.

The a priori assumption of Sigurdson et al, that homeopathic medicines cannot work and therefore must be nothing more than placebos, is itself a well-recognised source of bias. This ‘plausibility bias’4 blinds the researcher to the possibility that the beneficial effects of homeopathic medicines detected in placebo-controlled trials are real clinical effects, occurring via a non-biochemical mechanism of action, which has yet to be understood.

It is both disappointing and ironic that a study aimed at quantifying bias, is itself built entirely on a well-documented specific type of bias. Furthermore, when one considers the body of evidence demonstrating that homeopathic medicines have biological effects, not only in humans, but also in multiple animal5 and plant6 species, as well as molecular studies7, taking the stance that homeopathy is impossible, is clearly not evidence-based.


  1. Sigurdson MK, et al. Homeopathy can offer empirical insights on treatment effects in a null field. Journal of Clinical Epidemiology, 2023;155:64-72
  2. Mathie RT, et al. Randomised placebo-controlled trials of individualised homeopathic treatment: systematic review and meta-analysis, 2014;3:142
  3. Ioanniadis JP. Why most published research findings are false. PLoS Medicine, 2005;2:e124
  4. Rutten L, et al. Plausibility and evidence: the case of homeopathy. Medicine, Health Care and Philosophy, 2013;16(3):525-532
  5. Lopez-Carvallo JA, et al. Highly diluted bioactive compounds in marine aquaculture: A potential alternative for sustainable production. Reviews in Aquaculture, 2021;14(3):1170-1193
  6. Ücker A, et al. Systematic Review of Plant-Based Homeopathic Basic Research: An Update. Homeopathy, 2018; 107(2):115-129
  7. Tournier A, et al. Physicochemcial Investigations of Homeopathic Preparations: A Systematic Review and Bibliometric Analysis – Part 3. Journal of Alternative and Complementary Medicine, 2021;27(1):45-57