A prospective clinical trial was initiated to test the hypothesis that low-dose norepinephrine enhances urine output and renal function in oliguric surgical patients. Norepinephrine (0.05 or 0.1 micrograms/kg/min) was infused into nine oliguric (< or = 0.5 ml/kg/hr), volume-replete, hemodynamically stable patients. There was an average increase of urine output of 13 ml/hr (48% over baseline) and an increase of 31.7 ml/min (47% over baseline) in creatinine clearance. Both these results were statistically significant. Mean arterial pressure was the only hemodynamic parameter that changed significantly, rising an average of 12 mm Hg. We conclude that low-dose norepinephrine infusion may enhance renal function and urine output in acutely oliguric surgical patients who have been appropriately fluid resuscitated.