A study was conducted on a group of chronically hospitalized, brain-damaged male patients to assess the effectiveness of treatment with pindolol on behavioral problems. The study was conducted in two parts. The first was a double-blind, placebo-controlled analysis of the effect of pindolol on assaultive behavior, both verbal and physical. The second part was open and sought to determine whether pindolol would diminish such behaviors as resistance to care, sexual preoccupation, or provocation of others, which were sufficient to preclude placement at a lower level of care. These target behaviors and nursing interventions were monitored and clinical global assessments of improvement in behavior and of suitability for lower levels of care were developed. Eight of 13 patients were considered improved. Those with significant premorbid personality disorders showed little benefit. Pindolol appears to ameliorate some management problems and, by inference, improve the quality of life in many patients with behavioral pathology due to organic brain disease.