This chapter seeks to familiarize the readers with cholinergic and anticholinergic system. Acetylcholine (ACh) is the major neurotransmitter of parasympathetic nervous system (PSNS). ACh is degraded to choline + Acetic acid by enzyme. There are two types of acetylcholinesterase (AChE) i.e. true and pseudo. Actions of Ach include muscarinic actions and nicotinic actions. Anticholinergics are ALSO called antimuscarinics, parasympatholytics or cholinergic blocking drugs. They block the effects of ACh on muscarinic receptors. Classification, actions, adverse effects, and uses of anticholinergics are given in this chapter. At the end of this chapter there are questions along with their crisp and to the point answers have been also given, which will be of benefit for answering the short answers and even a viva voce question.