Agent Orange is a chemical herbicide and defoliant, one of the tactical uses of Rainbow Herbicides. It was used by the U.S. military as part of its herbicidal warfare program, Operation Ranch Hand, during the Vietnam War from 1961 to 1971. The U.S. was strongly influenced by the British who used Agent Orange during the Malayan Emergency. It is a mixture of equal parts of two herbicides, 2,4,5-T and 2,4-D.