AbstractFive Cebus apella monkeys with persistent neuroleptic‐induced dyskinesia were given a single dose of sulpiride (20 mg/kg i.m.). The dyskinesia was reduced in all five although four developed attacks of acute dystonia which had to be reversed by anticholinergic medication in three animals. In one monkey the administration of classic neuroleptics had earlier been shown to induce a typical sequence of events. First there was a similar reduction of dyskinesia as seen in the other monkeys, 1–2 days later there was noticed a rebound deterioration lasting for several days. Metoclopramide 0.5 mg/kg, caused such a rebound effect (for 2 days), whereas sulpiride did