Nerve gases, also known as nerve agents, are highly toxic organophosphorus compounds developed for use as chemical weapons. The chemical formula for the nerve agent Sarin, for example, is [(CH₃)₂CHO]CH₃P(O)F. Nerve agents are similar in function and chemical composition to organophosphorus insecticides but more toxic. Nerve agents, such as Tabun, Sarin, and Soman, are liquids that volatilize upon exposure to air. They may be released by rockets, bombs, explosives, or spray tanks. See also: Acetylcholine; Insecticide; Organophosphorus compound; Phosphorus; Toxicology; Toxin

Nerve agents in vapor, aerosol, or liquid form can be absorbed into the body by breathing, ingestion, or through the eyes and skin. Once inside the body, nerve agents disrupt the nervous system by inhibiting the action of the enzyme acetylcholinesterase, which breaks down the neurotransmitter acetylcholine. Acetylcholine causes various smooth and skeletal muscles to contract. By inhibiting the action of acetylcholinesterase, nerve agents prevent muscles from relaxing, causing organ failure and paralysis and ultimately death through asphyxiation. Nerve agents are fast acting, and can kill within minutes at low doses. Patients who have been exposed to nonlethal doses of organophosphate poisons may be treated with atropine and pralidoxime (2-pyridine aldoxime methyl chloride). See also: Atropine; Nervous system (vertebrate); Poison