['We hypothesize that treatment with Pravastatin, a HMG CoA reductase inhibitor would improve flow-mediated dilation (FMD), a nitric oxide dependent phenomenon and the earliest detectable marker of endothelial dysfunction, in asymptomatic patients with type-1 diabetes.', 'FMD of the brachial artery in response to reactive hyperaemia was measured using high-resolution ultrasonography. Young male patients with type-1 diabetes (n=9) were compared with age matched non-diabetic controls (n=8).', 'The FMD response in the control group was a median increase in diameter of 7.9 (range 3.8-12.6)%. In the diabetic group the FMD response was impaired when compared with controls with a median increase only of 4.4 (range 3.7-5.8)% (p<0.01). Following Pravastatin, 40 mg per day for one month in the diabetic group, there was a significant diameter change in response to reactive hyperaemia with a median of 8.4 (range 6.9-12.6)% (p<0.01).'] Does hydroxy-methylglutaryl-coenzyme A reductase inhibition improve endothelial dysfunction in type-1 diabetes?