This article originally appeared at the bbc.com
Agent Orange was the most notorious chemical defoliant sprayed by US forces over Vietnam to destroy jungles and vegetation during the Vietnam war.
Agent Orange contained dioxin, one of the most toxic chemicals known to man.
From the 1960s, doctors in Vietnam began to see a sharp rise in birth defects, cancers and other illnesses linked to exposure to Agent Orange
Decades later, Vietnamese are still being affected. Witness speaks to Dr. Nguyen Thi Ngoc Phuong about her struggle against the toxic legacy of the war.
Witness History: The stories of our times told by the people who were there.