The variation of capillary filtration rate (CFR), ankle circumference (AC), and ankle edema (AE) was evaluated in three groups of patients with venous hypertension (ambulatory venous pressure greater than 42 mmHg) and in a group of normal subjects before and after treatment for four weeks with Total Triterpenic fraction of Centella Asiatica (TTFCA), a venoactive drug acting on the microcirculation and on capillary permeability. Group A (20 patients) was treated with TTFCA 60 mg tid; Group B (20 patients) was treated with 30 mg tid; Group C (12 patients) was treated with placebo; and Group D (10 normal subjects) was treated with TTFCA 60 mg tid in an open study. Capillary filtration rate was assessed by venous occlusion plethysmography, ankle edema by a new system called AECT (Ankle edema coin tester). Subjective symptoms of venous hypertension were assessed by an analogue scale line considering four symptoms: swelling sensation, restless lower extremity, pain and cramps, and tiredness. CFR, AC, and AE were significantly higher in patients in comparison with normal subjects. After four weeks of TTFCA treatment there was a significant decrease of the abnormally increased CFR, AC, and AECT time in patients. This was also greater in the higher dose group. No significant change was observed in the placebo group and in normal subjects treated with TTFCA. Symptoms were also significantly improved in the two groups treated with the active drug according to the dose. No significant changes were observed in the placebo group.(ABSTRACT TRUNCATED AT 250 WORDS)