Hemorheological factors play an important role in the pathomechanism of ischemic cerebrovascular disorders. Abnormal rheological conditions in patients with chronic cerebrovascular disease predispose for recurrent strokes. Vinpocetine (VP), a synthetic ethyl esther of apovincamine, has successfully been used in the treatment of cerebrovascular diseases, in part because of its favourable rheological effects. The study investigates the hemorheological changes in 40 patients in the chronic stage of ischemic cardiovascular disease after administration of vinpocetine. All patients received a high dose of intravenous VP in doses gradually increased to l mg/kg/day. In addition, 20 patients (mean age: 61+/-8 years) received 30 mg VP orally for 3 months. The other 20 patients (mean age: 59+/-6 years), who received placebo tablets, served as controls. Hemorheological parameters (hematocrit, plasma fibrinogen, whole blood viscosity, red blood cell aggregation and deformability) were evaluated at 1 and 3 months. The high-dose parenteral VP significantly decreased red blood cell aggregation, plasma and whole blood viscosity (p < 0.05) compared to the initial values. In patients with additional oral treatment, plasma and whole blood viscosities were significantly lower compared to the placebo patients at 3 months (p < 0.05). Our results confirmed the beneficial rheological effects of high-dose parenteral VP (partially caused by hemodilution) observed previously, and also warrant its long-term oral admission to maintain the beneficial rheological changes.