Spa treatment is commonly used in chronic venous diseases, to the satisfaction of many patients, but no scientific validation work has been performed up to now. This pharmaco-clinical study was designed to evaluate the specific influence of topical application of the mineral water of La Léchère on the cutaneous microcirculation. It was a controlled, randomized, double-blind study comparing the effects of the water of La Léchère to distilled water applied as a spray to the ankle in ten healthy subjects. Skin temperature and laser-Doppler perfusion index (mean and temporal variability) were the evaluated parameters. Under these conditions, the results show a cutaneous cooling with a mean value of 0.3 to 0.5 degrees C, whose duration is significantly longer with the thermal water (p<0.05). During this cooling, the laser-Doppler perfusion index remained stable when distilled water was applied, whereas an increase was observed when the thermal water was employed (p=0.005). No significant changes in vasomotion were observed with either treatment (p=ns). This study demonstrates the presence of a specific effect of topical application of the La Léchère mineral water on the cutaneous microcirculation. The explanation and the potential therapeutic interest of this effect were beyond the scope of this study and remain to be investigated.