A probiotic turn is underway in the management of human and environmental health. Modern approaches are being challenged by deliberate interventions that introduce formerly taboo life forms into bodies, homes, cities and the wider countryside. These are guided by concepts drawn from the life sciences, including immunity and resilience. This analysis critically evaluates this turn, drawing on examples of rewilding nature reserves and reworming the human microbiome. It identifies a common ontology of socio-ecological systems marked by anthropogenic absences and tipped across thresholds into less desirable states. It examines the operation of an environmental mode of biopower associated with deliberate efforts to engineer ecologies through the introduction of keystone species. It offers a set of criteria for critically evaluating the degree to which these interventions transform or sustain prevalent forms of late modern biopolitics. The conclusion reflects on the potentials of probiotic environmentalities for hospitable government beyond the Anthropocene.
