Objectives: There is a need for preclinical test systems to assess specific effects of homeopathic
preparations in commonly available pharmaceutical form. We evaluated a plant bioassay
regarding its capacity to distinguish homeopathically prepared pillules from placebo.
Methods: Pea seed (Pisum sativum L. cv. Früher Zwerg) was soaked for 24 hours in water with dissolved homeopathic or placebo pillules.
Plants germinated and grew in a standard cultivation substrate under controlled environmental
conditions. Shoot length was measured 14 days after planting, and treatment groups
were compared by analysis of variance (ANOVA). After a screening, three independent
series of main experiments assessing the effects of Calcium carbonicum (12c, 30c, 200c) were performed with different experimenters in the same laboratory
to assess reproducibility. The stability of the system was validated by systematic
negative control experiments.
Results: No false positive results were observed in the systematic negative control experiments.
Placebo sucrose pillules did not influence shoot growth. A screening of 13 homeopathic
preparations revealed Calcium carbonicum 12c to affect pea shoot growth (p = 0.02). In the first series of repetition experiments (n = 8), Calcium carbonicum 30c influenced shoot growth (p = 0.04). In series II and III (n = 2 ×10), no significant main effect could be observed. A meta-analysis of all data
revealed the effect of Calcium carbonicum 12c and 30c to be dependent on the date of experiment and/or the experimental series.
Conclusion: The system is suitable to test a common application form—sucrose pillules—of a homeopathic
preparation without influence of the pharmaceutical carrier substance. We observed
some evidence that Calcium carbonicum 12c and 30c exerted specific effects in this bioassay. Further optimization of this
bioassay is necessary to be used in quality control or in investigating the biological
or pharmaceutical mode of action of homeopathic preparations.
Keywords: Homeopathy, anthroposophic medicine, homeopathic pillules, reproducibility, dwarf
peas, plant bioassay, Calcium carbonicum
