Chloracne is a disfiguring skin syndrome due to exposure to chlorinated organic compounds such as dioxin. The description of this condition begins at the dawn of the twentieth century in workers of chemical factories producing chlorine and caustic soda. Since the 1940s, the production of trichlorophenol and its use in the synthesis of the herbicide/defoliant 2,4-dichloro- and 2,4,5-trichlorophenoxyacetic acids caused the formation of dioxin as a contaminant, and many workers were exposed to dioxin and other chlorinated organic compounds. During the Vietnam war, tens of thousands of tons of a this herbicide mixture, the so-called "Agent Orange", were dropped on the Vietnamese population by the US army, and many people were intoxicated. Between the 1940s and the 1970s, several accidents happened in different chemical factories, releasing dioxin and derivatives in the atmosphere, exposing workers and local populations to various chloracnegen compounds. In 2004, a strange case of political poisoning occurred in Ukraine during the presidential campaign, and the victim, Victor Yushchenko, who developed a strong syndrome of chloracne, finally won the election. This book describes one century of chloracne history and dioxin contamination in various situations, and highlights the public health problem posed by this long lasting chemical waste. Although the chemical syntheses giving rise to the production of dioxin as a contaminant have been abandoned, dioxin and related compounds are still released from waste incinerators, and many populations in the world are exposed. Due to its very long biological half-life, dioxin accumulated in the organism, and more scientific studies are required to understand the consequences of the long-term accumulation of dioxin-like compounds on human health.