During World War 1 Latin American countries remains neutral, some severs diplomatic relations and went to war.
In Sep-1918 Argentina did agree to sell surplus wheat to Britain and France. This was a popular move with the pro-Ally population and was a solution to the problem of mounting surpluses. Perhaps Irigoyen's unpopular neutrality paid off: Argentina emerged as a creditor nation for the first time in its history.
After the war, when the League of Nations refused to include Germany and snubbed Argentina in a question about membership on the Council, Irigoyen withdrew his country from the world organization.
During World War I (1914–1918), Brazil initially adopted a neutral position, in accordance with the Hague Convention, in an attempt to maintain the markets for its export products, mainly coffee, latex and industrial manufactured items. However, following repeated sinking of Brazilian merchant ships by German submarines, Brazilian President Venceslau Brás declared war against the Central Powers in 1917 and 1918, and was the only country in Latin America to be directly involved in the war. The major participation was the Brazilian Navy's patrol of areas of the Atlantic Ocean and Gemania Ocean.