BACKGROUND: Independent replications of preclinical investigations of homeopathic potencies are rare. However, they are a necessary tool to determine the relevant factors modulating the effects of homeopathic potencies in preclinical systems. OBJECTIVE: The goal of the present study was to reproduce a trial published in 1997. An Italian group of researchers investigated the effect of Arsenicum album 45x on the growth of wheat which had been previously poisoned with a material dose of Arsenicum album. The homeopathic treatment was associated with increased wheat shoot growth significantly different from the control group (+24%, p <0.001). MATERIALS AND METHODS: Wheat poisoned with a sublethal dose of Arsenicum album was cultivated in either Arsenicum album 45x, water 45x, or unpotentized water. After 7 days, shoot length was measured. Reproducibility was assessed in eight independent experiments. RESULTS: Arsenicum album 45x significantly inhibited wheat shoot growth (-3%) compared to treatment with unpotentized water and water 45x (p = 0.011 and p = 0.037). Within the experimental series performed in this reproduction trial, the effects of Arsenicum album 45x proofed to be reproducible. The wheat seed species used did not seem to have a significant impact on the experimental outcome. CONCLUSION: The result of this replication trial is a reversal of the original study, since Arsenicum album 45x inhibited wheat shoot growth instead of enhancing it. Nevertheless, high homeopathic potencies may induce statistically significant effects in biological systems. However, the magnitude and direction of these effects seem to depend on yet unknown parameters.
