Volume 26, June 2016, Pages 146–163
Highlights
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- This review address the naive assumption that because of the generally diluted doses used homeopathy must be safe.
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- This review touches the neglected issue of the distinction between homeopathic aggravation, adverse reactions and adverse effects.
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- We found a similar risk for homeopathic treatment compared to controls such as placebo and conventional medicine
Abstract
Objectives
Homeopathy
 is a popular treatment modality among patient, however there is sparse 
research about adverse effects of homeopathy. A concept unique for 
homeopathy, is homeopathic aggravation that is understood as a transient
 worsening of the patients’ symptoms before an expected improvement 
occurs. From a risk perspective it is vital that a distinction between 
homeopathic aggravations and adverse effects is established. There is a 
lack of systematic information on how frequent adverse effects and 
homeopathic aggravations are reported in studies. Therefore, a 
systematic review and meta-analysis were performed.
Design and setting
Sixteen
 electronic databases were searched for Randomized Controlled Trials 
(RCTs). The searches were limited from the year 1995 to January 2011. 
Forty-one RCTs, with a total of 6.055 participants were included. A 
subtotal of 39 studies was included in the additional meta-analysis.
Results
A
 total of 28 trials (68%) reported adverse effects and five trials (12%)
 reported homeopathic aggravations. The meta-analysis (including six 
subgroup comparisons) demonstrated that no significant difference was 
found between homeopathy and control with OR 0.99, 95% CI 0.86–1.14, I2 = 54%.
 More than two third of the adverse effects were classified as grade 1 
(68%) and two third were classified as grade 2 (25%) and grade 3 (6%) 
according to the Common Terminology Criteria for Adverse Effects. 
Homeopathic aggravation was classified as grade 1 (98%) and grade 3 
(2%), suggesting that homeopathic aggravations were reported to be less 
severe than adverse effects. The methodological quality according to a 
method recommended in the Cochrane handbook for RCTs, was high.
Conclusion
Adverse
 effects including the concept of homeopathic aggravations are commonly 
reported in trials. The meta-analysis demonstrated that the proportion 
of patients experiencing adverse effects to be similar for patients 
randomized to homeopathic treatment compared to patients randomized to 
placebo and conventional medicine.
Keywords
- Adverse effects;
- Adverse events;
- Homeopathic aggravations;
- Patient safety;
- Systematic review;
- Meta-analysis;
- Risk assessment
© 2016 Elsevier Ltd. All rights reserved.
