A cholinergic crisis is an over-stimulation at a neuromuscular junction due to an excess of acetylcholine (ACh), as of a result of the inactivity (perhaps even inhibition) of the AChE enzyme, which normally breaks down acetylcholine. This is a consequence of some types of nerve gas, (e.g. sarin gas). In medicine, this is seen in patients with myasthenia gravis who take too high a dose of their cholinesterase inhibitor medications, or seen following general anaesthesia, when too high a dose of a cholinesterase inhibitor drug is given to reverse surgical muscle paralysis.