Infusions of 5% albumin and/or dextran 40 in nine patients with acute ischemic neurological deficits reduced mean hematocrit values from 41% to 32%, raised mean central venous pressure from 4 to 12 cm H2O, and reduced mean arterial BP from 101 to 94 mm Hg. Six alert patients had ischemic structural damage on cranial computed tomography. All six alert patients with upper arm paresis objectively improved and two others with only dysphasia also improved within 24 hours after infusion initiation. Although the improvement in two patients seemed to be temporarily dependent on the continuing of the infusion, all eight alert patients were eventually weaned without loss of regained function. This report of neurological improvement during hypervolemic hemodilution suggests that augmentation of collateral perfusion secondary to reduced blood viscosity may rapidly relieve cerebral ischemia, impede infarction, and allow time for compensatory mechanisms to maintain blood flow above ischemic thresholds.