The central anticholinergic syndrome should be considered in patients with altered mental status following anaesthesia. Physostigmine, a reversible acetylcholinesterase inhibitor, is a first-line medicament for the therapy of the central anticholinergic syndrome. Physostigmine crosses the blood-brain barrier and elevates acetylcholine levels in the brain. For prevention of postanaesthetic shivering, for treatment of intoxications and postoperative pain, and for patients suspected of having antimuscarinic delirium physostigmine is also indicated.