Preanaesthetic medication refers to the use of drugs before anaesthesia to make it safe and less unpleasant. When inhalation anaesthetic are given they inhibit the ciliary function therefore secretions in the respiratory pathway are not removed so we have to stop the secretions by administration of anti cholinergic drugs like atropine or glycopyrrolate. Glycopyrrolate is twice as potent and longer acting quaternary antimuscarinic which does not produce central effects. Antisecretory action is more marked than atropine and tachycardia is less marked. It acts rapidly when given i.v. and is the preferred antimuscarinic in anaesthetic practice.