It operated in the west during the American Civil War to help the U.S. Army deal with sick and wounded soldiers.
It was founded in St. Louis August 1861 under the protection of General John C. Frémont and under the leadership of Reverend William Greenleaf Eliot (1811–1887) and James E. Yeatman (1818–1901).
A major activity was acquiring adequate stocks of medicines and medical supplies for the hospitals run by the U.S. Army.
The money came from private fundraising in the city of St. Louis, as well as from donors in California and New England.
It also provided clothing and places to stay for freedmen and refugees, and set up schools for black children.