Acetylcholinesteraze is an enzyme that is used by the body to break down unused acetylcholine.

Neurons communicate with each other by means of chemical messages; molecules of a chemical, called a neurotransmitter, are released by one neuron and absorbed by other neurons who receive the message. Any remaining (unabsorbed) neurotransmitter is quickly cleaned up, to clear the way for new messages.

Acetylcholine is one important neurotransmitter, and acetylcholinesterase is an enzyme that inactivates unused acetylcholine, by breaking it down into its components (acetate and choline). These components can then be reabsorbed into the neurons and recycled back into acetylcholine for future use.

Cholinergic inhibitors are drugs that increase the efficiency of ACh by interfering with acetylcholinesterase.