Time-modulated Treatment Effects in Basic Homeopathic Research. The Moment Matters!

Background: Homeopathy is a form of medicine that has been practised for over two centuries and is popular in many parts of the world, but remains controversial. To address this controversy, we developed a very simple bioassay to facilitate replication and multi-center trials without the need for sophisticated equipment. Cress seeds ( Lepidium sativum L.) were grown in vitro within Ca(NO 3 ) 2 salt tolerance levels, on the assumption that homeopathic preparations would induce compensatory effects, which would likely be more pronounced in impaired plants. Preparation screening experiments revealed unambiguous, highly significant growth-modulating effects for several preparations at different potentiation levels. During a subsequent experimental phase, we assessed possible chronobiological time-modulated effects of the 30x preparations. Methods: Verum and systematic negative control (SNC) experiments were performed with Acidicum nitricum , Carbo vegetabilis , Natrium muriaticum , Nux vomica, and Phosphorus at 0.5 g/L Ca(NO 3 ) 2 , applying 160 cress seeds per condition, in ten independent experiments (replications), on subsequent experimental days. Results: The treatment effect of the initial screening experiments could not be replicated in these subsequent experiments. Instead, highly significant time-modulated treatment effects ( p < 0.001) were identified for cress treated with Carbo vegetabilis, Nux vomica, and Phosphorus , and significant time-modulated treatment effects ( p ≤ 0.01) were identified for Natrium muriaticum . Interestingly, the mean treatment effect for all individual preparations was consistently higher in the initial screening experiment. As was the case in the screening experiments, no significant modulation of seedling lengths was found for cress treated with Nitricum acidicum compared with the vehicle control. Evaluation of the SNC experiments indicated a stable experimental setup and a reliable treatment effect. Conclusion: The phenomenon of temporal modulation of homeopathic treatment effects has been repeatedly reported in basic homeopathic research and may represent a more common phenomenon that is under-reported. Possible reasons for such effects are discussed.