Morphine was administered intravenously in bolus doses 6-hourly to 10 patients; 9 developed signs of sympathetic overactivity and required increased morphine dosage. The mean daily morphine dosage was 103 +/- 36 mg and the maximum daily dosage was 170 +/- 65 mg. In all cases morphine decreased the mean arterial blood pressure (mean 18%; P less than 0.01) and heart rate (mean 7%; P less than 0.01). In 7 cases the cardiac output fell minimally (mean 7%; P = 0.07), while the systemic vascular resistance decreased (mean 12%; P less than 0.01) in 8 cases. Nine patients survived, 1 died from renal failure and septicaemia. There were no apparent problems with either opiate withdrawal or addiction. No patient required either alpha- or beta-adrenergic blockers and the consequent simplified management constitutes a significant improvement in control of these patients.