With the beginning of World War I, Topîrceanu was drafted, then taken prisoner and imprisoned by Bulgarian forces during the Battle of Turtucaia, in September 1916. He was kept in a POW camp until the end of the war, in 1918. After his return, Topîrceanu published several volumes of wartime recollections: "Amintiri din luptele de la Turtucaia" ("Memories from Battle of Turtucaia", 1918), "În ghiara lor... Amintiri din Bulgaria și schițe ușoare" ("In Their Claw... Memories from Bulgaria and Light Sketches", 1920), and "Pirin-Planina, epizoduri tragice și comice din captivitate" ("Pirin-Planina, Tragic and Comical Episodes from Captivity", 1936) - which represent, among others, a vivid depiction of the profound effects that the cholera epidemic had on the morale of Romanian troops during their attempted retreat.