We investigated the influence of a 2.2 mmol/L fluvastatin solution on the intracellularly recorded membrane potential and flow-dep- endent tension of isolated human intracerebral arteries from consc- iousness areas, coming from brain surgery. The flow of the blood substitute solutions was varied in the steps 3,5,20,40, and 100 mL /min. In the controls (n=6), the smooth muscle cells of the brain arteries hyperpolarized from ?49.1±0.6 mV (3 mL/min) to ?52.5 ±0.4 mV (100 mL/min) (p<0.0007). Simultaneously, the blood vessels, stretched by 1.5 g pretension, relaxed from 1.398±0.011 g to 1.028±0.025 g (p<0.0001) corresponding to 26.5% of their initi- al tone. Under fluvastatin (n=6), membrane hyperpolarization and decrease in wall tension were much more distinct. The membrane potential of ?50.7±0.3 mV hyperpolarized against the controls al- ready with a flow rate of 3 mL/min, became even more negative with increasing flow, up to ?56.6±0.4 mV at a flow rate of 100 mL/min (p<0.0001). Wall tension decreased from 1.369±0.024 g (3 mL/min) to 0.822±0.038 g (100 mL/min) (p<0.0001). This is equivalent to a 40% reduction in tension. The augmentation of flow-dependent dilatation is underlined by increase of the cGMP- concentration determined after 100 mL/min flow from 1.13±0.30 (15) in Krebs solution to 4.32±0.80 (15) upon fluvastatin addition (p<0.0009). Thus, fluvastatin improves endothelial function. This vasodilation may have a beneficial effect on cognitive functions in dementiae of Alzheimer type, in prevention of TIA and stroke.