Noninvasive ultrasonic biopsy (UB) can be used to classify arteriosclerotic lesions and their progression in the carotid and femoral bifurcation. Also the evaluation of intima-media thickness (IMT) is useful to quantify the progression of early arteriosclerosis. Two randomly selected groups of asymptomatic subjects were included in a 18 month, open study. One group was treated with oral mesoglycan (200 mg/day) and one group was followed-up as control. The two groups were comparable for age and sex distribution. The average UB score was 14.4 +/- 5 in the treatment group and 14.3 +/- 8 in the control group. After 18 months the UB score was 15.7 +/- 4 in the treatment and 16.2 +/- 6 in the control group. These differences were not significant. However the average increase in IMT in 18 months in the treatment group was 0.016 mm equivalent to 0.0106 mm per year. In the control group the average increase was 0.119 equivalent to 0.0793 per year. Therefore the increase in IMT was 7.48 times greater in the control group. These differences were significant (p < 0.05). Two drop-outs were recorded in the treatment group and 1 in the control group. In conclusion IMT measurements showed a decreased level of IMT progression in subjects under mesoglycan treatment. These results need to be confirmed by a larger randomised study.