Agent Orange was an herbicide developed by the United States government for use in the Vietnam War.
Agent Orange, so named for the orange cannisters it came in, was originally designed to kill and wipe out all the vegetation in the Vietnamese jungles, clearing out entire forests, allowing war to be easier. The North Vietnamese Army was mostly made of guerilla soldiers who, despite being poorly armed, had a very good understanding of their environment, allowing them to easily beat the Americans. The government hoped that Agent Orange would give them an advantage by killing the vegetation. It killed some vegetation, but not on the scale the US Military had hoped for, and there were deadly side effects. Agent Orange was soon found to cause severe cases of cancer among returning veterans.