In the last century, the deliberate use of chemical warfare has inflicted mass casualties and remarkable psychological consequences on the public. A historical summary of the most relevant chemical warfare agents is reported, as well as the main advantages and disadvantages to the use of chemical weapons in warfare or terrorist attacks in the beginning of the 21^st century. Toxic aggressives are described according to their physiopathologic effects on the human body. Some prevalent key myths about chemical weapons are discussed and discredited. Even though the risk of use of chemical agents for warfare purposes has diminished over the past years, these weapons still represent a potential threat in episodes of national and international terrorism. Accurate information and basic training campaigns for civilian populations can reduce anxiety levels, improve the general preparedness, and limit the terrorists' capacity for harm.