During Clara Barton's last years with the American National Red Cross, the organization was criticized for its inefficiency and came under rebuke during the Spanish-American War from Surgeon General George M. Sternberg, who believed that women nurses should not be permitted on the battlefield but instead should be confined to base hospitals. Sternberg appointed physician and anthropologist Anita Newcomb McGee (1864-1940) as acting assistant surgeon general and charged her with recruiting qualified graduate nurses to staff army hospitals and later to serve in overseas camps. At the end of the war, McGee helped organize a permanent Army Nurses Corps. Her papers (3,000 items; 1688-1932) document her medical and army careers as well as her role in forming the Women's Anthropological Society of America and her research on communal societies in the United States, including the Shakers and the Oneida community.

The discord within the American National Red Cross was fueled in part by a power struggle between Clara Barton and newly appointed executive committee member Mabel Thorp Boardman (1860-1946), who eventually succeeded Barton as the organization's leader in 1904. Boardman's papers (4,000 items; 1853-1945; bulk 1904-29), which include extensive correspondence with William Howard Taft and other national officials, trace the Red Cross's growing ties to the federal government and its emergence as the leading voluntary organization providing disaster and war relief and promoting public health and safety.

During the First World War, more than eighteen thousand Red Cross nurses served with the Army and Navy Nurse Corps. Some of these nurses—such as Dorothy Kitchen O'Neill (70 items; 1918-19), who was stationed at American Red Cross headquarters in Savenay, France—worked at American base hospitals, at field units, and aboard ships, whereas others, including Helen Culver Kerr (200 items; 1918-19), served at home combating the 1918 influenza epidemic and providing medical services to military camps, munitions plants, and shipyards.

Some American Red Cross nurses served as part of the British Expeditionary Force (B.E.F.). Edith Hulsizer Copher (1891-1935), for example, went to France as a dietitian with a B.E.F. Red Cross unit formed by Dr. Harvey Cushing of the Harvard Medical School, and her letters in the Hulsizer Family Papers (145 items; 1915-41; bulk 1917-19) provide not only an account of the medical conditions in army facilities but a glimpse of the social life and everyday concerns of the young hospital staff.

The long hours, stress, and exposure to disease took a toll on army medical personnel. Obituaries in the Breckinridge Family Papers (205,000 items; 1752-1965) suggest that fatigue and overwork contributed to the death of Mary Curry Desha Breckinridge (d. 1918), a Red Cross nurse who joined a Chicago hospital unit serving in France during the war. Several hundred letters written to and from Breckinridge describe her experiences.

At the start of World War I, Red Cross official Grace Elizabeth Allen (1886-1976) was just entering nursing school in Washington, D.C. Several volumes of her meticulous diary in the Allen Family Papers (500 items; 1865-1976) discuss her training and wartime work at Columbia Hospital in the nation's capital.