Homeopathy for COVID-19 in primary care: A randomized, double-blind, placebo-controlled trial (COVID-Simile study).
Ubiratan Cardinalli Adler et al. (2022) · Journal of integrative medicine
This randomized, double-blind, placebo-controlled trial with 86 analyzed participants explored whether a homeopathic remedy could help people recover faster from mild COVID-19 while isolating at home in Brazil. Homeopathy is a medical system built on the "principle of similars" - the idea that a highly diluted substance capable of causing symptoms in a healthy person can treat similar symptoms in someone who is sick. The remedy tested, Natrum muriaticum (a homeopathic preparation of sodium chloride, common salt), was prepared using Samuel Hahnemann's fifty-millesimal (LM) method: repeated 1:50,000 dilutions with vigorous shaking (succussion) between steps, governing how homeopaths believe a remedy's potency rises as its material dose falls. Adults with a positive PCR test for SARS-CoV-2 and flu-like symptoms were randomly assigned to take drops of Natrum muriaticum LM2 or an identical-looking placebo every six hours (more often if symptoms were severe) during home isolation. Researchers tracked recovery by phone and WhatsApp, asking participants to rate 15 to 17 symptoms - including cough, fatigue, and loss of smell or taste - on a 0-to-3 severity scale, then combined these into a daily symptom score analyzed with Kaplan-Meier survival curves, the statistical method used to track time-to-event outcomes like recovery. The main result was a null one: time to full symptom recovery did not differ significantly between the homeopathy and placebo groups (P = 0.56 overall, P = 0.06 among the most symptomatic participants) - homeopathy showed a numerically shorter median recovery time (3 days versus 6 days) in the sicker subgroup, but the gap was not statistically reliable. A secondary analysis told a more encouraging, though still tentative, story: among participants who started with a high symptom burden, those taking homeopathy reached a 50% reduction in symptoms significantly faster than those on placebo (P = 0.04), improving roughly 0.9 days sooner over the first five days (P = 0.022) - though this edge disappeared by day 7 and day 10, suggesting it may reflect the natural course of a self-limiting illness rather than a true treatment effect. Hospitalization was numerically lower with homeopathy (2.4% versus 6.8%) but not statistically significant, and side effects were mild and similar between groups. For patients and clinicians, this trial does not provide evidence to recommend homeopathic Natrum muriaticum LM2 as a COVID-19 treatment - the confidence intervals around the promising secondary findings were too wide to draw firm conclusions, and the study fell short of its planned 90-participant sample after dropouts left 86. Baseline differences between groups, including more respiratory disease in the homeopathy arm, add further uncertainty. The authors frame this as a pioneering but inconclusive first step, calling for larger, more targeted trials - particularly in patients with more severe symptoms at enrollment - before homeopathy's role in COVID-19 care can be assessed.