<p>Recent research has highlighted the profound connection between the gut microbiome and overall human health, particularly its impact on mental well-being. The potential of “psychobiotic” interventions to foster resilience and emotional stability is especially promising. Methodologically, this article offers a philosophical–theological exploration that interprets current microbiome research in dialog with Christian theological sources, emphasizing how human–microbe symbiosis shapes both mental health and theological understandings of the human person. The intricate relationship between the microbiome, mental health, and brain function, in turn, affects spirituality and challenges anthropocentric notions of human identity. Certain anthropological and theological perspectives suggest that the gut microbiome can be viewed as a divine gift that enhances human flourishing through symbiosis. Within this framework, the human person appears as a <i>holobiont</i>-a composite of body, soul, and microbial life-created for communion with God and others. As steward and priest of creation, the human–holobiont is called to actively participate in the divine work of creation and redemption through relational communion with others, including fellow humans, the natural environment, and the microbiota. Integrating scientific insights with theological reflection, this article proposes that microbiome care contributes not only to mental well-being but also to spiritual restoration and ecological ethics. A non-egocentric eco-Christological ethic could thus honor microbiome care as integral to human personhood and divine relationship, fostering harmony between humanity, creation, and the divine.</p> Graphical Abstract <p></p>