With B-mode ultrasound measurements of the intima-media thickness (IMT) of the carotid arterial wall (asymptomatic) atherosclerosis can be detected. In this article several studies are reviewed in which IMT was used as a surrogate endpoint to assess effects of lipid-lowering or antihypertensive drugs on peripheral atherosclerosis, and the clinical implications are discussed. After 1 year of treatment with lipid-lowering drugs an improvement of the blood lipid profile and retarded progression of the carotid IMT was seen. No incontrovertible evidence can be provided for a correlation between induced changes in the carotid and coronary arteries. Carotid IMT appears to be of prognostic value for cardiovascular events. The range of treatment-induced changes in IMT do not support the use of IMT in an individual patient to monitor treatment effects. However, with increased IMT as independent cardiovascular risk factor, IMT measurements are valuable in risk assessment in the individual patient in clinical practice. Looking forward to some ongoing studies, there is so far insufficient evidence that treating hypertension also inhibits progression of the IMT.