In the present international climate, preparedness and effectively responding to chemical terrorism is of serious concern. Given that antidotes are available for chemical agents, such as nerve or blood (cyanide) agents, the key to survival is how quickly and effectively antidotes can be administered in mass casualty events. To counter agents acting on the nervous system, atropine, pralidoxime and diazepam are generally administered, but aside from pralidoxime, no general consensus has been reached regarding the use of oximes, such as obidoxime and HI-6. In addition, the use of diazepam is being investigated in comparison to other benzodiazepines. As antidotes to blood agents, sodium nitrite (or amyl nitrite) and sodium thiosulfate are often used in the United States, but in Europe, dicobalt edetate and hydroxocobalamin are used. In particular, hydroxocobalamin appears to be a promising antidote against blood-agent terrorism. In mass casualty events caused by chemical terrorism, it is also necessary to consider the most effective administration routes of the antidote (intravenous, intramuscular or intraosseous). Hence, it is imperative to adequately discuss when first responders (rescuers) wearing personal protective equipment (PPE) should administer these drugs and who should be in charge of such drug administration. Here these problems are reviewed and discussed with reference to the current literature.