A graduate of the Royal Victoria Hospital in Montréal, Dorothy Cotton was one of 37 nurses who were sent to serve in Russia during the First World War. In May 1915, as part of the Canadian Expeditionary Force, Dorothy travelled overseas with the No. 3 Canadian General Hospital, a special project of McGill University, and served in England and France for 6 months. From November 1915 to June 1916, Dorothy served with the Anglo-Russian hospital in Petrograd before she was recalled to England. Dorothy returned to Petrograd to serve from January to August 1917, then returned to England and was appointed acting matron at an officer's hospital in London. She was later transferred to Halifax until her demobilization in August 1919.

The Dorothy Cotton fonds held by Library and Archives Canada includes a diary dated from November 2, 1915 to July 1, 1916, created by Dorothy as a record of reports she completed in Russia for the Canadian Army Medical Corps (CAMC). The fonds also contains letters to Dorothy's family, written between December 1915 and December 1916.