A parasympathomimetic drug is a drug or poison that acts by stimulating or mimicking the parasympathetic nervous system (PSNS). These chemicals are also called cholinergics because acetylcholine (ACh) is the neurotransmitter used by the PSNS. Chemicals in this family can act either directly by stimulating the nicotinic or muscarinic receptors, or indirectly by inhibiting cholinesterase, promoting acetylcholine release, or other mechanisms. 
- Choline esters
- Plant alkaloids
Indirect acting parasympathomimetic drugs may be either reversible cholinesterase inhibitors, irreversible cholinesterase inhibitors or drugs that promote ACh release or Anti-adrenergic. The latter inhibits the antagonistic system, the sympathetic nervous system.
- Reversible cholinesterase inhibitors
- Irreversible cholinesterase inhibitors
- ACh release promoters
- Brenner, G. M. (2000). Pharmacology. Philadelphia, PA: W.B. Saunders Company. ISBN 0-7216-7757-6