Drug-induced dyskinesia due to neuroleptic or l-dopa therapy is a well-known phenomenon although little is known about its pathophysiology. On the other hand, dyskinesia due to anti-cholinergic treatment has rarely been reported and then most often when PD patients were on concomitant l-dopa therapy . There are a few reports of anticholinergic-induced dyskinesia in other conditions, including dystonia and/or tremor (esupp: Table 1 and Refs. 1–4). In these reports, dyskinesia subsided within 2 months following drug withdrawal.