Systematic Review of Plant-Based Homeopathic Basic Research: an Update
05 February 2020 (online)
Background and Aims: Plant-based test systems have been described as a useful tool for investigating possible effects of homeopathic preparations. The last reviews of this research field were published in 2009/2011. Due to recent developments in the field, an update is warranted. Publications on plant-based test systems were to be analysed with regard to publication quality, reproducibility and potential for further research.
Methods: A literature search was conducted in online databases and specific journals, including publications from 2008 to 2017 dealing with plant-based test systems in homeopathic basic research. To be included, they had to contain statistical analysis and fulfil quality criteria according to a pre-defined manuscript information score (MIS), ranging from 0–10. Publications scoring at least five points were included. They were analysed for use of adequate controls, outcome and reproducibility.
Results: 74 publications on plant-based test systems were found. 26 reached an MIS of 5 or higher. Adequate controls were used in 13 of these publications. All of them reported on specific effects of homeopathic preparations. The publication quality is still varied: a substantial number of publications (23%) did not adequately document the methods used. Four reported on replication trials. One replication trial found effects of homeopathic preparations comparable to the original study; three replication trials failed to confirm the original study but identified possible external influencing factors. Five publications described novel test systems. Eight trials used systematic negative control experiments to investigate test system stability.
Conclusions: Quality of publications has increased continuously in the period investigated. Regarding research design, future trials should implement adequate controls to identify specific effects of homeopathic preparations and include systematic negative control experiments to document test system stability. Further external and internal reproduction trials, and control of influencing factors, are needed to verify results.
Keywords: Homeopathy, plant-based test systems, review