Faced with pervasive loss, life threat, and moral conflict in the field of battle, the human body and brain adapt to extraordinary circumstances in extraordinary ways. These adaptations come at a high price, and many men and women returning from Iraq and Afghanistan are paying that price every day. For the clinician who seeks to help, an understanding of the physiology of war-zone stress and resilience is an essential foundation, both for recovery from post-traumatic stress disorder and other conditions, and for addressing the stigma and shame that keep many service members and veterans from seeking and accepting the help and support they need. This article explores ways in which the body and brain adapt to war-zone stress, resulting challenges, and implications for clinical services and ongoing recovery.