Chronic use of levodopa may be complicated by dyskinesias, on-off effect, or hallucinosis. Transient levodopa withdrawal (drug holiday) may increase motor responsiveness and decrease levo-dopa-induced side effects, and the improved state may persist for as long as 9 months. After 1 year, parkinsonian signs approached pre-holiday levels, and two of the patients required a 'second drug holiday; side effects began to reappear 9 to 12 months after the holiday. Four of six patients with psychiatric complications remained free of hallucinations for the entire year.