This paper proposes the unification of ecophysiology and ecotoxicology into a novel research field, ecophysiotoxicology, underpinned by hormesis as a broadly generalizable biological principle through which low-dose stress commonly activates adaptive, compensatory, or protective responses, whereas higher doses cause inhibition or damage. Here, an adaptive response denotes an inducible biological adjustment and is not synonymous with heritable evolutionary adaptation or an unconditional net fitness benefit. The integration combines mechanistic tools from ecophysiology, including stressor-induced molecular, metabolic, and physiological adjustments, with ecological scaling and dose-response tools from ecotoxicology to predict multistressor effects across biological hierarchies. Hormesis provides the new theoretical bridge, placing natural and anthropogenic stressors on a shared dose-dependent continuum, while the two disciplines contribute complementary explanatory and predictive strengths. The synthesis addresses critical gaps in global change biology by incorporating stressor dissimilarity, exposure timing, eco-evolutionary dynamics, and explicit translation from mechanisms to population, community, and ecosystem outcomes. A concise workflow and two applied scenarios show how the proposed field is intended to support testable predictions, strengthen risk assessment, and evaluate priming or resilience-enhancing interventions without assuming that every stimulatory response is beneficial at every biological level.



