Regulatory agencies have to ensure the end-user safety of botanically derived homeopathic medicines prepared with diluted starting materials derived even from toxic plants. In the case of plant-derived homeopathic products, assessment must consider the particular characteristics of an extract and its component molecules, even if diluted. The identification and quantification of these molecules have a crucial role in risk assessment, as it allows complete toxicological evaluation in a regulatory perspective. Different results can be achieved using different approaches and references supported by the same regulatory framework, as different methods of preparation used, assays and test analysis performed in compliance with different referent pharmacopoeias. All these facts can introduce a bias in the safety assessment and the paradoxical outcome for homeopathic Adonis vernalis underlines the need for caution. The case also demonstrates the relevance of considering the analytical method for assessment of all herbal medicinal products or herbal supplements, with the purpose of finding the total amount of toxicants as a good approach.© 2020 John Wiley & Sons, Ltd.