The VSC (vacuum suction chamber) device, a new system to evaluate local capillary permeability, was used with laser Doppler flowmetry to study variations of permeability and of the microcirculation in 10 normal subjects; in 22 patients with moderate, superficial venous hypertension; and in 12 patients with postphlebitic limbs and severe venous hypertension. All these patients had distal (ankle and foot edema) in the evening. After a first assessment these subjects were studied again after two weeks without treatment and after two weeks' treatment with total triterpenic fraction of centella asiatica (TTFCA), tablets, 60 mg, tid. The VSC produces a wheal on the skin of the perimalleolar region that disappears (in average) in less than sixty minutes in normal subjects. The disappearance time (DT) is greater in conditions of increased capillary filtration and permeability. The three groups of subjects (normal and those with superficial and severe venous hypertension) had significantly different, increasing disappearance time of the wheals at the first observation. There were no significant changes after two weeks' observation, but after 2 weeks' treatment with TTFCA, there was a significant decrease of DT both in limbs with superficial and with deep venous incompetence. The improvement (decrease) of the abnormally increased capillary permeability was associated with a significant improvement of the microcirculation and symptoms (studied by an analogue scale line). In conclusion this study showed a combined improvement of the microcirculation and capillary permeability after treatment with TTFCA and the possibility of using the VSC to evaluate the effects of drugs (or other treatment) on local capillary permeability in patients with venous hypertension.