The pathophysiology, anticholinergic therapy and dopaminergic therapy of Parkinson's disease are reviewed; an emphasis is placed on the structure and function of the basal ganglia because of their importance in understanding the pharmacotherapy of parkinsonism. The pharmacologic management of Parkinson's disease is limited primarily to manipulation of the dopamine-acetylcholine system. Levodopa, with or without a peripheral dopa decarboxylase inhibitor, is the current drug of choice in the management of idiopathic and postencephalitic Parkinson's disease. Modification of the serotonin-histamine system via the use of antihistamines may be useful in some patients. There are also many adjunctive agents which may be employed in combination with or in place of levodopa. Levodopa clearly has no place in the treatment of neuroleptic-induced Parkinson's disease; anticholinergics and antihistamines are the agents of choice.