This chapter focuses on the complexity and multi-faceted nature of the history of military medicine in wartime. The First World War was a war of unprecedented slaughter, not only leaving millions dead, but millions wounded, who, as a result of the violence and the unhealthy circumstances, were accompanied by millions of sick soldiers. The sheer numbers of wounded tell the tale of medical care stretched to its limits and every once in a while beyond them. The whole structure of medical care changed in wartime. Medical care aimed not only to repair but also to prepare such men to resume their place in society. It also aimed to reduce the pension lists by giving injured men the care they needed to get back to work. Medical care strengthened the war effort of each combatant army, just as it would do later in the twentieth century in later wars.