This article investigates opiate addiction among Civil War veterans. Although historians have long known that many veterans developed opiate addictions, previous scholarship has neglected the lived experience of addiction and its myriad consequences for veterans in their postwar lives. Drawing upon a sample of a hundred cases, this article argues that opiate addiction caused overwhelming suffering for Civil War veterans, chiefly because “slavery” to opiates—as addiction was often described—violated prevailing ideals of manhood, morality, and mental health. Opiate addiction spelled disaster for veterans’ health and undermined claims to manhood and good moral character. Addiction also limited veterans’ access to pensions and soldiers’ homes and often resulted in involuntary commitment to mental institutions. By uncovering these previously unknown dimensions of opiate addiction, this article furthers scholarly efforts to account for the disastrous personal consequences of the Civil War for many veterans.