Since the first report in 1977, many studies have been carried out to determine the efficacy of beta- blockers such as propranolol for the treatment of violent and aggressive behaviour. Propranolol has also been used in the treatment of dementia, attending- deficit disorder, schizophrenia, personality disorders, Korsakoff,s psychosis, posttraumatic stress disorder, profound mental retardation, autism and brain injury. Doses of prescribed propranol have been varied from 60 to 1440 mgs per day. Though the mea range 260 to 400 mg per day is more common . In the present study, 4 patients diagnosed as paranoid schizophrenia, bipolar mood disorder, mental retardation, and disorganized schizophrenia who did not respond to the conversational drug treatment were chosen. Propranolol with doses higher than 250 mg/ day was administered. The main symptoms and signs targeted for the treatment were; severe aggression, impulsive homicidal outburst, grossly impaired functioning . Propranolol was administered in doses of 250_440 mg/ day ( high doses) and higher doses were not required. According to the clinical psychiatrist and the reports from the nursing staff and patients relatives, the efficacy of propranolol in high doses was satisfactory. This study suggests that further similar controlled investigations are needed to be carried out in different areas.