This chapter explores the intricate interplay between music, emotions, and the body’s regulatory systems – the autonomic nervous system, hormones, and the immune system. It elucidates how music influences physiological responses, such as heart rate, breathing, and hormone levels, and how these changes can impact health and well-being. The chapter looks at the dual roles of the sympathetic and parasympathetic nervous systems in regulating bodily functions, highlighting how music can modulate their activity. It also discusses the complex interplay of hormones such as cortisol, adrenaline, and noradrenaline, emphasizing the distinction between healthy and unhealthy stress. Research findings on the effects of music on cortisol levels are presented, demonstrating how relaxing music tends to decrease cortisol, while activating music tends to increase it. Both responses can be beneficial, depending on the context and individual needs. Furthermore, the chapter explores the impact of music on the immune system, and underlines the importance of positive emotions and moods in promoting a healthy immune response. Overall, this chapter provides a comprehensive overview of how music interacts with our physiological systems, offering insights into its therapeutic potential for both healthy individuals and those facing health challenges.