Curcumin is shown to commonly induce biphasic dose responses in a broad range of cell types, with particular emphasis on neural cells, including neuronal stem cells. The quantitative features of these biphasic dose responses, with respect to the magnitude and width of the low dose stimulation, are similar to those reported for hormetic dose responses. These hormetic dose responses occur within the framework of direct stimulatory responses as well as in preconditioning experimental protocols, displaying acquired resistance within an adaptive homeodynamic framework. These findings have important implications for study design strategies involving dose selection and spacing, as well as sample size and statistical power considerations. These findings further reflect the broadly general occurrence of hormetic dose responses that consistently appear to be independent of biological model, endpoint, inducing agent and mechanism.