An eyewitness of the Battle of Solferino (Solferino, Battle of) (June 24, 1859), which resulted in nearly 40,000 casualties, Dunant organized emergency aid services for the Austrian and French wounded. In Un Souvenir de Solférino (1862; A Memory of Solferino), he proposed the formation in all countries of voluntary relief societies for the prevention and alleviation of suffering in war and peacetime, without distinction of race or creed; he also proposed an international agreement covering the war wounded. In 1863 he founded the International Committee for the Relief of the Wounded (now International Committee of the Red Cross), and the following year the first national societies and the first Geneva Convention (Geneva Conventions) came into being.

Having gone bankrupt because he neglected his business affairs, Dunant left Geneva in 1867 and spent most of the rest of his life in poverty and obscurity. He continued to promote interest in the treatment of prisoners of war, the abolition of slavery, international arbitration, disarmament, and the establishment of a Jewish homeland. After he was “rediscovered” by a journalist in Heiden, Switzerland, in 1895, Dunant received many honours and annuities.