HI-6 is an oxime that stops the damage caused by nerve gas. Nerve gas attacks the nervous system by blocking the enzyme acetylcholinesterase(AChE) from breaking down neurotransmitters, causing nerves to remain active when they shouldn't be, see Nerve Agents for a full explanation. HI-6 reactivates the enzyme and stops the progress of the nerve agent. Normally HI-6 is carried by soldiers and administered with atropine in case of nerve gas attacks.