Several key principles of homeopathy feature in this issue of the journal. The first of our papers, however, features the physiological principle of preconditioning, whose specific example here is enhancing the therapeutic efficacy of mesenchymal stem cells by prior modulation of the cells’ culture conditions. The in-vitro study by Aphale and colleagues offers evidence that homeopathic Arsenicum enhanced the cells’ capacity to reduce a lipopolysaccharide-induced cytokine storm in blood mononuclear cells.[1] That a homeopathic remedy may increase immunomodulatory potential in this way is a noteworthy finding. Whether water is itself potentised in the process of preparing a homeopathic medicine is a principle that is methodically addressed in the paper by Cartwright & Pinkus.[2] Using a solvatochromic dye to detect the presence of potencies it was found that, compared with Arsenicum 10M, ‘Water 10M’ did not potentise. Water thus appears to be merely an inert carrier for the potentisation of substances placed in it, laying to rest any remaining considerations that water has a ‘memory’.