Adverse Effects of Homeopathy

A Systematic Review of Published Case Reports and Case Series

P. Posadzki; A. Alotaibi; E. Ernst


Int J Clin Pract. 2012;66(12):1178-1188. 

In This Article

Abstract and Introduction


Aim: The aim of this systematic review was to critically evaluate the evidence regarding the adverse effects (AEs) of homeopathy.

Method: Five electronic databases were searched to identify all relevant case reports and case series.

Results: In total, 38 primary reports met our inclusion criteria. Of those, 30 pertained to direct AEs of homeopathic remedies; and eight were related to AEs caused by the substitution of conventional medicine with homeopathy. The total number of patients who experienced AEs of homeopathy amounted to 1159. Overall, AEs ranged from mild-to-severe and included four fatalities. The most common AEs were allergic reactions and intoxications. Rhus toxidendron was the most frequently implicated homeopathic remedy.

Conclusion: Homeopathy has the potential to harm patients and consumers in both direct and indirect ways. Clinicians should be aware of its risks and advise their patients accordingly.


Homeopathy can be defined as 'a therapeutic method that often uses highly diluted preparations of substances whose effects when administered to healthy subjects correspond to the manifestation of the disorder (symptoms, clinical signs and pathological states) in the unwell patient'.[1] It is one of the most popular form of complementary and alternative medicine in the UK and elsewhere.[2] The reasons for this widespread use are probably complex, but the assumption that homeopathy is safe is certainly an important factor.[1]

Although most homeopathic remedies are highly diluted, direct adverse effects (AEs) have been reported.[3] Indirect risks mainly relate to replacing effective conventional treatments with ineffective homeopathic preparations.[3,4]

The aim of this systematic review was to provide a summary and critical evaluation of the published evidence regarding direct and indirect AEs associated with homeopathy.