Cholinergic syndrome is a toxidrome, or a set of symptoms associated with poisoning from certain substances. Symptoms are predominantly caused by activation of muscarinic receptors that control the parasympathetic nervous system.

Symptoms include bradycardia, wheezing, diaphoresis, miosis, diarrhea, and salivation. Activation of nicotinic acetylcholine receptors can also cause hypertension. Muscarinic effects result from parasympathetic overstimulation (miosis and blurred vision; excessive secretions, especially salivation, lacrimation, urination, defecation, gastric cramping, and emesis [SLUDGE]).

Drugs that can induce cholinergic syndrome include organophosphates (insecticides), carbamates, cholinergic drugs such as physostigmine, and nicotine. Cholinergic syndrome can be life-threatening.

Treatment is with anticholinergic drugs, such as atropine. Pralidoxime is additionally used in cases of organophosphate poisoning.