The work of the Red Cross has been greatly expanded since the end of World War II, and it has moved into many fields. It has taken on extensive refugee relief activities, helping to care for refugees of warfare, drought, and ethnic conflicts all over the world, including Hungary (1956), Somalia (1992), Rwanda (1994), and the former Yugoslavia (throughout the 1990s). During the Korean War, the International Red Cross suggested (1952) the first exchange of prisoners and sick and wounded combatants. The group also coordinated international relief efforts following natural disasters, such as the massive cyclone and storm surge that hit East Pakistan (now Bangladesh) in 1970 and left almost a half million dead, the hurricane that hit Honduras in 1974, and the earthquakes in Armenia (1988) and Turkey (1999).

The American Red Cross was organized (1881) by Clara Barton and received its first federal charter in 1900. In 1905, it was brought into closer relationship with the government when a new congressional charter was granted. The charter was revised in 1947. The organization, with headquarters in Washington, D.C., is supported entirely by voluntary contributions. The president of the United States is honorary chairman of the society, responsible for the appointment of its president and seven other members of its board of governors. The American Red Cross puts special emphasis on disaster relief, services to the armed forces and veterans, and public health and safety programs. The nationwide Red Cross blood program is a comprehensive system designed to collect, store, treat, and distribute blood and blood products to the ill and injured throughout the United States (see blood bank).

The creation of the Red Cross was spurred by the publication of Un Souvenir de Solférino (1862), an account by Jean Henri Dunant of the suffering endured by the wounded at the battle of Solferino in 1859. Dunant, a Swiss citizen, urged the formation of voluntary aid societies for relief of such war victims. He also asked that service to military sick and wounded be neutral.

The Société genovoise d'Utilité publique, a Swiss welfare agency, actively seconded Dunant's suggestion, the result being the formation (1863) of the organization that became known as the Red Cross. The next year, delegates from 16 nations met in Switzerland, and the Geneva Convention of 1864 for the Amelioration of the Condition of the Wounded and Sick of Armies in the Field was adopted and signed by 12 of the nations represented. It provided for the neutrality of the medical personnel of armed forces, the humane treatment of the wounded, the neutrality of civilians who voluntarily assisted them, and the use of an international emblem to mark medical personnel and supplies. In honor of Dunant's nationality, a red cross on a white background—the Swiss flag with colors reversed—was chosen as this symbol.

The original Geneva Convention, its subsequent revisions, and allied treaties such as the Hague Convention for naval forces and the Prisoner of War Convention have been signed (although not always ratified) by almost all countries and their dependencies. The International Committee of the Red Cross was awarded the Nobel Peace Prize in 1917, 1944, and, with the League of Red Cross Societies, in 1963.

The Red Crescent, which was first used by the Ottoman Empire in 1876, was formally recognized by the League of Red Cross Societies in 1929. Iran used the Red Lion and Sun, formally recognized in 1949, until 1980. The adoption of the Red Crystal symbol in 2005 (effective in 2007), although occurring primarily as a means to provide an emblem under which Israel's Magen David Adom could become a full member (2006) of the international movement, also established a neutral emblem that could be used by any national society that preferred to avoid using the Christian cross or Islamic crescent.