Its war-time predecessor had been formed in Winnipeg on 7 November 1914 and served in France and Flanders 1915–1919 as part of the 2nd Canadian Division.
During the Second World War, 4 Field Ambulance formed another active service unit, which served first in Italy and later in France and Belgium.
Medical staff, who were involved early in the planning of the invasion of Italy, developed a plan to evacuate casualties back to the landing beaches where additional clearing stations and field surgical units, as well as special beach medical sections would be located.
One such proposal was to withdraw the issue of short pants from the troops as they tended to leave these on after dark when mosquitoes became active.
At this time the Canadian axis of advance was moving mainly to the east coast road and soon Locri was in 3rd Brigade hands.