Health communication is central to prevention and care, yet generic messages frequently fail to achieve real behaviour change. Personalisation offers a way forward by aligning health information with individual characteristics. This chapter examines why one-size-fits-all approaches are limited, how tailored strategies can improve engagement and adherence, and what challenges must be addressed to ensure equity and trust. We also discuss how emerging technologies, including large language models, create new opportunities for scalable, evidence-based personalisation. Ultimately, we argue that personalised health communication is not a refinement but a strategic necessity for improving outcomes across healthcare systems.