Homeopathic Dilution

H J Hamre et al. (2023) · Systematic reviews

This systematic review examined six earlier meta-analyses (statistical pooling studies) of placebo-controlled randomized trials of homeopathy for any health condition in humans, asking whether homeopathy shows an effect beyond placebo. Homeopathy is built on drug provings (recording symptoms in healthy people), the principle that a substance causing a symptom pattern is used to treat a similar one, and potentization, which means serial dilution with vigorous shaking. Because the six meta-analyses, published between 1997 and 2017, used different methods and reached different conclusions, the authors reviewed them together under a published protocol and judged their risk of bias and the certainty of the overall evidence. The authors searched eight databases plus a private collection and contacted experts, identifying 16 reports covering six meta-analyses, with searches running to December 2020 and an update to April 2023. Two reviewers screened and extracted data independently. The meta-analyses together covered 310 trials or trial comparisons (182 distinct trials published between 1943 and 2014), most often on respiratory conditions such as allergic rhinitis and influenza. Each meta-analysis was rated for risk of bias with ROBIS, and the combined evidence was graded with a GRADE-based approach. All five meta-analyses with reported pooled estimates found a significant effect favouring homeopathy across all trials, for example an odds ratio of 2.45 (95% CI 2.05-2.93) across 89 trials in the 1997 analysis and a standardized mean difference of 0.33 (0.21-0.44) across 54 non-individualised trials in 2017. When only high-quality trials were kept, three of four analyses stayed significant, but the 2017 analysis did not (SMD 0.18, -0.09 to 0.46, 3 trials). Only 6-29% of trials met each analysis's high-quality criteria. Three analyses showed significant heterogeneity and funnel plot asymmetry, a pattern that can signal publication or small-study bias; individualised homeopathy showed neither. Two analyses that combined quality and trial-size restrictions found no significant difference from placebo. Three meta-analyses were rated low and three high risk of bias. The authors rated evidence certainty as high for individualised homeopathy and moderate for the other categories. The authors conclude that the data do not support the hypothesis of no difference from placebo and that placebo-controlled evidence gives no justification for regulatory action against homeopathy. The review only covers trials already in six meta-analyses, so trials after 2011 (individualised) and 2014 (non-individualised) are missing. It also reports no indication-specific results, and its use of GRADE tested whether any effect exists rather than how large it is. The authors recommend updating the individualised homeopathy analysis and studying specific non-individualised treatments for specific conditions.

Monika Kujawska et al. (2019) · Journal of ethnobiology and ethnomedicine

This historical review examined Bryonia alba (white bryony), a vine in the cucumber family, tracing its use across northern and central-eastern Europe from antiquity through the twentieth century. The authors, an ethnobiologist and an ethnologist, worked from written and oral sources rather than a clinical study, covering Sweden, Denmark, Germany, Poland, Belarus, Ukraine, Romania and the Balkans. White bryony's root closely resembles the root of mandrake (Mandragora officinarum), a plant with an extensive European magical and medicinal reputation; the paper's central finding is that this resemblance let bryony function as mandrake's cheaper stand-in, inheriting much of its folklore in the process. Rather than enrolling participants, the authors searched historical floras, pharmacopoeias, ethnographic monographs, and travel accounts for every mention of the plant, then sorted findings into categories: ritual and folk-belief use, food, folk and historical medicine, ethnoveterinary practice, and ornamental planting. They cross-checked, where sources allowed, whether a given account referred to B. alba or its close relative B. dioica, and separated practices documented only in printed herbals ("booklore") from those recorded as living oral tradition passed between households. Across independent sources, root preparations were repeatedly recorded for oedema (fluid swelling, called dropsy at the time), convulsions and epilepsy, intestinal worms, wounds, and rheumatic pain — a 1792 Swedish account describes juice collected from a hollowed-out root curing oedema and treating worms, convulsions and headache, while twentieth- and twenty-first-century accounts from Serbia and Kosovo describe the same root used as a purgative, diuretic and topical anti-rheumatic agent. The authors cite phytochemical literature attributing these effects to cucurbitacins (bitter plant compounds), also linked elsewhere to antitumor activity, while stating plainly that historical claims for epilepsy specifically lack sufficient supporting study. Toxicity is dose- and season-dependent: freshly harvested summer root contains the more toxic cucurbitacin I, and the berries carry a cited lethal dose of roughly 15 for a child and 40 for an adult. The authors report that medicinal use had become obsolete across Scandinavia, Germany and western Slavic regions by the twentieth century, surviving only in isolated Balkan communities in Serbia and Kosovo. The authors present this decline as an unusual case: a plant of substantial historical medicinal and magical importance that today survives mainly as an ornamental garden relic or, in North America, as an unrelated invasive weed. Because the review synthesizes historical and ethnographic records rather than testing the plant directly, it offers no controlled data on safety or effectiveness, and the authors themselves flag some recorded folklore as possibly the invention of root sellers rather than genuine tradition. Future work, the authors suggest, could extend this same source-based method to B. dioica across German-, Latin- and Celtic-speaking Europe.