Haloperidol is safe and effective in children for relieving psychotic symptoms associated with childhood autism, schizophrenia and mental retardation. It is the drug of choice for Tourette's syndrome, and may be useful in nonpsychotic hyperactive or aggressive children to control acute episodes, or when the stimulants normally useful in hyperactive children are ineffective. Such children taking haloperidol not only become calmer, but are often better able to respond to other modalities of therapy and to school instruction. Dosage, initially low, is increased gradually to minimize drowsiness and extrapyramidal symptoms, the most common side effects. Haloperidol in children is usually well-tolerated.