How Safe Are Homeopathic Medicines; A Look at the Evidence

By Michelle L. Dossett, MD, PhD, MPH, FACP 

The safety of medicines is a key concern for patients, clinicians, and regulatory officials. Adverse effects of medications are common and can range from mild to life-threatening and, in rare cases, can even cause death. A meta-analysis examining 33 studies of adverse drug reactions in more than 1.5 million patients in the primary care setting found that the prevalence of adverse drug reactions was 8.3%; that nearly half of these adverse drug reactions interfered with work, leisure, or daily life; and that somewhere between 1–9% of them required a visit to the emergency department or hospitalization.¹

Compared to conventional pharmaceutical medications, homeopathic medicines have a much better track record for safety. A meta-analysis examining 41 randomized controlled trials and more than 6,000 patients found that homeopathic medicines were associated with a similar adverse effect rate as placebos (odds ratio [OR] 1.03, 95% confidence interval [CI] 0.89 – 1.20).² Among the adverse effects reported, 65% were considered mild, 32% moderate, and 4% severe/medically significant based on information in the primary publications. Notably, only five of the included studies reported on homeopathic aggravations, and 98% of these were classified as mild (2% severe/significant).

A reanalysis of this data by another group came to similar, but slightly different conclusions. They found that homeopathic medicines were associated with significantly more adverse effects than placebos (OR = 1.42, 95% CI 1.15 – 1.76), but significantly fewer adverse effects compared to conventional medicines (OR = 0.64, 95% CI 0.43 – 0.96).³

Another meta-analysis of 16 observational studies (8,164 participants) found that homeopathic medicines were associated with significantly fewer adverse effects than conventional pharmaceutical medications used as controls (e.g., NSAIDs, antibiotics, corticosteroids, nasal preparations, and analgesics), OR 0.83 (95% CI 0.76 – 0.92, p = 0.0004).⁴ Among the adverse effects seen in the homeopathy groups, 55% were mild, 42% moderate, and 3% severe. A total of nine studies examined in the same paper reported on homeopathic aggravations. There were 97 total aggravations (3.2% of participants) with 47% of these considered minor and 53% moderate.

In addition to data from clinical trials, there are a number of case reports that claim adverse effects related to homeopathic medicines. Unfortunately, the largest collection of these reports is poorly written and contains insufficient background information regarding concurrent treatments, coexisting disease states, and the homeopathic product(s) ingested to adequately ascertain the underlying causes of the adverse effects observed.^3,5 However, there are some well-documented case reports with adequate evidence to suggest adverse effects associated with homeopathic medicines, especially when they are used frequently in low attentions over an extended period of time⁶ or due to alcohol content of the preparation interacting with other medications.⁷ Moreover, any experienced homeopath knows that while homeopathic medicines are incredibly safe, they can cause adverse effects when misused or cause aggravations in certain situations, especially with highly sensitive individuals.

In summary, these studies suggest that the overall rates of adverse effects associated with homeopathic medicines (particularly in the hands of skilled practitioners in research settings) is relatively low and significantly lower than adverse effects seen with conventional pharmaceuticals. Moreover, serious/medically significant adverse effects related to homeopathic medicines were rare, and there were no reports of life-threatening or fatal adverse effects related to homeopathic medicines in clinical trials.