The efficacy and safety of remoxipride in the treatment of schizophrenia were compared with those of haloperidol in a multicentre double-blind 6-week study which was randomized with a parallel group design and was preceded by a washout period. Eighty-nine consecutively admitted men and women meeting the Research Diagnostic Criteria for schizophrenia in an acute phase of the illness were treated with remoxipride 75-300 mg twice daily or haloperidol 5-20 mg twice daily. The efficacy assessments were the Brief Psychiatric Rating Scale, Krawiecka Rating Scale, and Clinical Global Impression. Both antipsychotic drugs produced clinical improvement with no significant differences between the efficacy of the two drugs. There were relatively few side effects. There were significantly fewer extrapyramidal symptoms and instances of blurred vision with remoxipride and less constipation with haloperidol. The results indicate that remoxipride is as effective an antipsychotic as haloperidol. Remoxipride has an advantage over haloperidol in respect to extrapyramidal side effects.