The aim of this open study was the evaluation of the effects of HR (Venoruton) at a dose of 1 g/day on the prevention and control of flight microangiopathy and edema in subjects with varicose veins and moderate chronic venous insufficiency flying for more than 11 hours. Patients with varicose veins, edema, but without initial skin alterations or complications, were included. Measurements of skin laser Doppler (LDF) resting flux (RF) venoarteriolar response (VAR), ankle swelling (RAS), and edema were made within 12 hours before and within 3 hours after the flights. The resulting edema after the flights was evaluated with a composite edema score (analogue scale line). A group of 20 subjects was treated with HR (1 g/day, starting 2 days before the flight and 1 g for every 12 hours on day of travel). Another group of 18 subjects formed the control group. The length of the flights was between 11 and 13 hours; all seats were in coach class. Fifty patients were enrolled and 38 patients were evaluable at the end of the trial. The 2 groups (treatment and control) were comparable for age and sex distribution. The decrease in RF was significant in both groups with a higher flux at the end of the flight in the HR group (p < 0.05). The venoarteriolar response was decreased at the end of the flights; the decrease was lower in the HR group (p < 0.05). The increase in RAS and the edema score were significantly lower in the HR group. In conclusion HR is useful for reducing the level of microangiopathy and the increased capillary filtration and in controlling edema in patients with venous disease in long flights. The higher level of flux and VAR and the reduction in edema indicate a positive effect of HR on the microcirculation. This study confirms that HR prophylaxis is effective to control flight microangiopathy associated with edema.